Moved many API calls over to new version 4.

Old versions are marked as deprecated. All new API calls are documented.

13 files changed, 711 insertions, 33 deletions

diff --git a/examples/tapi b/examples/tapi
index cb37c03..4495a73 100755
--- a/examples/tapi
+++ b/examples/tapi
@@ -12,7 +12,7 @@
 #  You can set the following environment variables (default in brackets):
 #    TAGINFO_API_SERVER   [taginfo.openstreetmap.org]
 #    TAGINFO_API_PORT     [80]
-#    TAGINFO_API_VERSION  [2]
+#    TAGINFO_API_VERSION  [4]
 #
 
 require 'rubygems'
@@ -23,7 +23,7 @@ require 'json'
 
 API_SERVER  = ENV['TAGINFO_API_SERVER']  || 'taginfo.openstreetmap.org'
 API_PORT    = ENV['TAGINFO_API_PORT']    || 80
-API_VERSION = ENV['TAGINFO_API_VERSION'] || '2'
+API_VERSION = ENV['TAGINFO_API_VERSION'] || '4'
 
 def api_call(path, params)
     query = []
diff --git a/web/lib/api/db.rb b/web/lib/api/db.rb
index 9c2f5e5..c5bfe01 100644
--- a/web/lib/api/db.rb
+++ b/web/lib/api/db.rb
@@ -9,6 +9,7 @@ class Taginfo < Sinatra::Base
     }
 
     api(2, 'db/keys', {
+        :superseded_by => '4/keys/all',
         :description => 'Get list of keys that are in the database or mentioned in any other source.',
         :parameters => { :query => 'Only show keys matching this query (substring match, optional).' },
         :paging => :optional,
@@ -138,6 +139,7 @@ class Taginfo < Sinatra::Base
     end
 
     api(2, 'db/tags', {
+        :superseded_by => '4/tags/popular',
         :description => 'Get list of most often used tags.',
         :parameters => { :query => 'Only show tags matching this query (substring match in key and value, optional).' },
         :paging => :optional,
@@ -195,6 +197,7 @@ class Taginfo < Sinatra::Base
     end
 
     api(2, 'db/keys/overview', {
+        :superseded_by => '4/key/stats',
         :description => 'Show statistics for nodes, ways, relations and total for this key.',
         :parameters => { :key => 'Tag key (required).' },
         :paging => :no,
@@ -275,6 +278,7 @@ class Taginfo < Sinatra::Base
     end
 
     api(2, 'db/keys/distribution', {
+        :superseded_by => '4/key/distribution/nodes',
         :description => 'Get map with distribution of this key in the database (nodes only).',
         :parameters => { :key => 'Tag key (required).' },
         :result => 'PNG image.',
@@ -293,6 +297,7 @@ class Taginfo < Sinatra::Base
     end
 
     api(3, 'db/keys/distribution/nodes', {
+        :superseded_by => '4/key/distribution/nodes',
         :description => 'Get map with distribution of this key in the database (nodes only).',
         :parameters => { :key => 'Tag key (required).' },
         :result => 'PNG image.',
@@ -311,6 +316,7 @@ class Taginfo < Sinatra::Base
     end
 
     api(3, 'db/keys/distribution/ways', {
+        :superseded_by => '4/key/distribution/ways',
         :description => 'Get map with distribution of this key in the database (ways only).',
         :parameters => { :key => 'Tag key (required).' },
         :result => 'PNG image.',
@@ -329,6 +335,7 @@ class Taginfo < Sinatra::Base
     end
 
     api(2, 'db/keys/values', {
+        :superseded_by => '4/key/values',
         :description => 'Get values used with a given key.',
         :parameters => {
             :key => 'Tag key (required).',
@@ -409,6 +416,7 @@ class Taginfo < Sinatra::Base
     end
 
     api(2, 'db/keys/keys', {
+        :superseded_by => '4/key/combinations',
         :description => 'Find keys that are used together with a given key.',
         :parameters => {
             :key => 'Tag key (required).',
@@ -511,6 +519,7 @@ class Taginfo < Sinatra::Base
     end
 
     api(2, 'db/tags/overview', {
+        :superseded_by => '4/tag/stats',
         :description => 'Show statistics for nodes, ways, relations and total for this tag.',
         :parameters => {
             :key => 'Tag key (required).',
@@ -590,6 +599,7 @@ class Taginfo < Sinatra::Base
     end
 
     api(2, 'db/tags/combinations', {
+        :superseded_by => '4/tag/combinations',
         :description => 'Find keys and tags that are used together with a given tag.',
         :parameters => {
             :key => 'Tag key (required).',
diff --git a/web/lib/api/key.rb b/web/lib/api/key.rb
new file mode 100644
index 0000000..bee71d8
--- /dev/null
+++ b/web/lib/api/key.rb
@@ -0,0 +1,260 @@
+# web/lib/api/key.rb
+class Taginfo < Sinatra::Base
+
+    api(4, 'key/stats', {
+        :description => 'Show some database statistics for given key.',
+        :parameters => { :key => 'Tag key (required).' },
+        :result => {
+            :type           => :STRING,
+            :count          => :INT,
+            :count_fraction => :FLOAT,
+            :values         => :INT
+        },
+        :example => { :key => 'amenity' },
+        :ui => '/keys/amenity#overview'
+    }) do
+        key = params[:key]
+        out = []
+
+        # default values
+        ['all', 'nodes', 'ways', 'relations'].each_with_index do |type, n|
+            out[n] = { :type => type, :count => 0, :count_fraction => 0.0, :values => 0 }
+        end
+
+        @db.select('SELECT * FROM db.keys').
+            condition('key = ?', key).
+            execute() do |row|
+                ['all', 'nodes', 'ways', 'relations'].each_with_index do |type, n|
+                    out[n] = {
+                        :type           => type,
+                        :count          => row['count_'  + type].to_i,
+                        :count_fraction => (row['count_'  + type].to_f / get_total(type)).round_to(4),
+                        :values         => row['values_' + type].to_i
+                    }
+                end
+        end
+
+        return {
+            :total => 4,
+            :data => out
+        }.to_json
+    end
+
+    api(4, 'key/distribution/nodes', {
+        :description => 'Get map with distribution of this key in the database (nodes only).',
+        :parameters => { :key => 'Tag key (required).' },
+        :result => 'PNG image.',
+        :example => { :key => 'amenity' },
+        :ui => '/keys/amenity#map'
+    }) do
+        key = params[:key]
+        content_type :png
+        @db.select('SELECT png FROM db.key_distributions').
+            condition("object_type='n'").
+            condition('key = ?', key).
+            get_first_value() ||
+        @db.select('SELECT png FROM db.key_distributions').
+            condition('key IS NULL').
+            get_first_value()
+    end
+
+    api(4, 'key/distribution/ways', {
+        :description => 'Get map with distribution of this key in the database (ways only).',
+        :parameters => { :key => 'Tag key (required).' },
+        :result => 'PNG image.',
+        :example => { :key => 'highway' },
+        :ui => '/keys/highway#map'
+    }) do
+        key = params[:key]
+        content_type :png
+        @db.select('SELECT png FROM db.key_distributions').
+            condition("object_type='w'").
+            condition('key = ?', key).
+            get_first_value() ||
+        @db.select('SELECT png FROM db.key_distributions').
+            condition('key IS NULL').
+            get_first_value()
+    end
+
+    api(4, 'key/values', {
+        :description => 'Get values used with a given key.',
+        :parameters => {
+            :key => 'Tag key (required).',
+            :lang => "Language for description (optional, default: 'en').",
+            :query => 'Only show results where the value matches this query (substring match, optional).'
+        },
+        :paging => :optional,
+        :filter => {
+            :all       => { :doc => 'No filter.' },
+            :nodes     => { :doc => 'Only values on tags used on nodes.' },
+            :ways      => { :doc => 'Only values on tags used on ways.' },
+            :relations => { :doc => 'Only values on tags used on relations.' }
+        },
+        :sort => %w( value count_all count_nodes count_ways count_relations ),
+        :result => {
+            :value       => :STRING,
+            :count       => :INT,
+            :fraction    => :FLOAT,
+            :description => :STRING
+        },
+        :example => { :key => 'highway', :page => 1, :rp => 10, :sortname => 'count_ways', :sortorder => 'desc' },
+        :ui => '/keys/highway#values'
+    }) do
+        key = params[:key]
+        lang = params[:lang] || 'en'
+        filter_type = get_filter()
+
+        if @ap.sortname == 'count'
+            @ap.sortname = ['count_' + filter_type]
+        end
+
+        (this_key_count, total) = @db.select("SELECT count_#{filter_type} AS count, values_#{filter_type} AS count_values FROM db.keys").
+            condition('key = ?', key).
+            get_columns(:count, :count_values)
+
+        if params[:query].to_s != ''
+            total = @db.count('db.tags').
+                condition("count_#{filter_type} > 0").
+                condition('key = ?', key).
+                condition_if("value LIKE '%' || ? || '%'", params[:query]).
+                get_first_value()
+        end
+
+        res = @db.select('SELECT * FROM db.tags').
+            condition("count_#{filter_type} > 0").
+            condition('key = ?', key).
+            condition_if("value LIKE '%' || ? || '%'", params[:query]).
+            order_by(@ap.sortname, @ap.sortorder) { |o|
+                o.value
+                o.count_all
+                o.count_nodes
+                o.count_ways
+                o.count_relations
+            }.
+            paging(@ap).
+            execute()
+
+        # Read description for tag from wikipages, first in English then in the chosen
+        # language. This way the chosen language description will overwrite the default
+        # English one.
+        wikidesc = {}
+        ['en', lang].uniq.each do |lang|
+            @db.select('SELECT value, description FROM wiki.wikipages').
+                condition('lang = ?', lang).
+                condition('key = ?', key).
+                condition("value IN (#{ res.map{ |row| "'" + SQLite3::Database.quote(row['value']) + "'" }.join(',') })").
+                execute().each do |row|
+                wikidesc[row['value']] = row['description']
+            end
+        end
+
+        return {
+            :page  => @ap.page,
+            :rp    => @ap.results_per_page,
+            :total => total.to_i,
+            :data  => res.map{ |row| {
+                :value    => row['value'],
+                :count    => row['count_' + filter_type].to_i,
+                :fraction => (row['count_' + filter_type].to_f / this_key_count.to_f).round_to(4),
+                :description => wikidesc[row['value']]
+            } }
+        }.to_json
+    end
+
+    api(4, 'key/combinations', {
+        :description => 'Find keys that are used together with a given key.',
+        :parameters => {
+            :key => 'Tag key (required).',
+            :query => 'Only show results where the other_key matches this query (substring match, optional).'
+        },
+        :paging => :optional,
+        :filter => {
+            :all       => { :doc => 'No filter.' },
+            :nodes     => { :doc => 'Only values on tags used on nodes.' },
+            :ways      => { :doc => 'Only values on tags used on ways.' },
+            :relations => { :doc => 'Only values on tags used on relations.' }
+        },
+        :sort => %w( together_count other_key from_fraction ),
+        :result => {
+            :other_key      => :STRING,
+            :together_count => :INT,
+            :to_fraction    => :FLOAT,
+            :from_fraction  => :FLOAT
+        },
+        :example => { :key => 'highway', :page => 1, :rp => 10, :sortname => 'together_count', :sortorder => 'desc' },
+        :ui => '/keys/highway#keys'
+    }) do
+        key = params[:key]
+        filter_type = get_filter()
+
+        if @ap.sortname == 'to_count'
+            @ap.sortname = ['together_count']
+        elsif @ap.sortname == 'from_count'
+            @ap.sortname = ['from_fraction', 'together_count', 'other_key']
+        end
+
+        cq = @db.count('db.keypairs')
+        total = (params[:query].to_s != '' ? cq.condition("(key1 = ? AND key2 LIKE '%' || ? || '%') OR (key2 = ? AND key1 LIKE '%' || ? || '%')", key, params[:query], key, params[:query]) : cq.condition('key1 = ? OR key2 = ?', key, key)).
+            condition("count_#{filter_type} > 0").
+            get_first_value().to_i
+
+        has_this_key = @db.select("SELECT count_#{filter_type} FROM db.keys").
+            condition('key = ?', key).
+            get_first_value()
+
+        res = (params[:query].to_s != '' ?
+            @db.select("SELECT p.key1 AS other_key, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.keypairs p, db.keys k WHERE p.key1=k.key AND p.key2=? AND (p.key1 LIKE '%' || ? || '%') AND p.count_#{filter_type} > 0
+                    UNION SELECT p.key2 AS other_key, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.keypairs p, db.keys k WHERE p.key2=k.key AND p.key1=? AND (p.key2 LIKE '%' || ? || '%') AND p.count_#{filter_type} > 0", key, params[:query], key, params[:query]) :
+            @db.select("SELECT p.key1 AS other_key, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.keypairs p, db.keys k WHERE p.key1=k.key AND p.key2=? AND p.count_#{filter_type} > 0 
+                    UNION SELECT p.key2 AS other_key, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.keypairs p, db.keys k WHERE p.key2=k.key AND p.key1=? AND p.count_#{filter_type} > 0", key, key)).
+            order_by(@ap.sortname, @ap.sortorder) { |o|
+                o.together_count
+                o.other_key
+                o.from_fraction
+            }.
+            paging(@ap).
+            execute()
+
+        return {
+            :page  => @ap.page,
+            :rp    => @ap.results_per_page,
+            :total => total,
+            :data  => res.map{ |row| {
+                :other_key      => row['other_key'],
+                :together_count => row['together_count'].to_i,
+                :to_fraction    => (row['together_count'].to_f / has_this_key.to_f).round_to(4),
+                :from_fraction  => row['from_fraction'].to_f.round_to(4)
+            } }
+        }.to_json
+    end
+
+    api(4, 'key/wiki_pages', {
+        :description => 'Get list of wiki pages in different languages describing a key.',
+        :parameters => { :key => 'Tag key (required)' },
+        :paging => :no,
+        :result => {
+            :lang             => :STRING,
+            :language         => :STRING,
+            :language_en      => :STRING,
+            :title            => :STRING,
+            :description      => :STRING,
+            :image            => :STRING,
+            :on_node          => :BOOL,
+            :on_way           => :BOOL,
+            :on_area          => :BOOL,
+            :on_relation      => :BOOL,
+            :tags_implies     => :ARRAY_OF_STRINGS,
+            :tags_combination => :ARRAY_OF_STRINGS,
+            :tags_linked      => :ARRAY_OF_STRINGS
+        },
+        :example => { :key => 'highway' },
+        :ui => '/keys/highway#wiki'
+    }) do
+        key = params[:key]
+
+        res = @db.execute('SELECT * FROM wikipages WHERE value IS NULL AND key = ? ORDER BY lang', key)
+
+        return get_wiki_result(res)
+    end
+
+end
diff --git a/web/lib/api/keys.rb b/web/lib/api/keys.rb
new file mode 100644
index 0000000..13f1ea1
--- /dev/null
+++ b/web/lib/api/keys.rb
@@ -0,0 +1,183 @@
+# web/lib/api/keys.rb
+class Taginfo < Sinatra::Base
+
+    @@filters = {
+        :characters_space       => { :expr => "characters='space'",   :doc => 'Only show keys with spaces.' },
+        :characters_problematic => { :expr => "characters='problem'", :doc => 'Only show keys with problematic characters.' },
+        :in_wiki                => { :expr => "in_wiki=1",            :doc => 'Only show keys that appear in the wiki.' },
+        :not_in_db              => { :expr => "count_all=0",          :doc => 'Only show keys that do not appear in the database.' }
+    }
+
+    api(4, 'keys/all', {
+        :description => 'Get list of all keys.',
+        :parameters => { :query => 'Only show keys matching this query (substring match, optional).' },
+        :paging => :optional,
+        :filter => @@filters,
+        :sort => %w( key count_all count_nodes count_ways count_relations values_all users_all in_wiki in_josm in_potlatch length ),
+        :result => {
+            :key                      => :STRING, 
+            :count_all                => :INT,
+            :count_all_fraction       => :FLOAT,
+            :count_nodes              => :INT,
+            :count_nodes_fraction     => :FLOAT,
+            :count_ways               => :INT,
+            :count_ways_fraction      => :FLOAT,
+            :count_relations          => :INT,
+            :count_relations_fraction => :FLOAT,
+            :values_all               => :INT,
+            :users_all                => :INT,
+            :in_wiki                  => :BOOL,
+            :in_josm                  => :BOOL,
+            :in_potlatch              => :BOOL
+        },
+        :example => { :page => 1, :rp => 10, :filter => 'in_wiki', :sortname => 'key', :sortorder => 'asc' },
+        :ui => '/keys'
+    }) do
+
+        if params[:filters]
+            filters = params[:filters].split(',').map{ |f| @@filters[f.to_sym][:expr] }.compact
+        else
+            filters = []
+        end
+
+        include_data = Hash.new
+        if params[:include]
+            params[:include].split(',').each{ |inc| include_data[inc.to_sym] = 1 }
+        end
+
+        total = @db.count('db.keys').
+            condition_if("key LIKE '%' || ? || '%'", params[:query]).
+            conditions(filters).
+            get_first_value().to_i
+        
+        res = @db.select('SELECT * FROM db.keys').
+            condition_if("key LIKE '%' || ? || '%'", params[:query]).
+            conditions(filters).
+            order_by(@ap.sortname, @ap.sortorder) { |o|
+                o.key
+                o.count_all
+                o.count_nodes
+                o.count_ways
+                o.count_relations
+                o.values_all
+                o.users_all
+                o.in_wiki
+                o.in_josm
+                o.in_potlatch
+                o.length 'length(key)'
+                o.length :key
+            }.
+            paging(@ap).
+            execute()
+
+        if include_data[:wikipages]
+            reshash = Hash.new
+            res.each do |row|
+                reshash[row['key']] = row
+                row['wikipages'] = Array.new
+            end
+
+            wikipages = @db.select('SELECT key, lang, title, type FROM wiki.wikipages').
+                condition("value IS NULL").
+                condition("key IN (#{ res.map{ |row| "'" + SQLite3::Database.quote(row['key']) + "'" }.join(',') })").
+                order_by([:key, :lang], 'ASC').
+                execute()
+
+            wikipages.each do |wp|
+                key = wp['key']
+                wp.delete_if{ |k,v| k.is_a?(Integer) || k == 'key' }
+                reshash[key]['wikipages'] << wp
+            end
+        end
+
+        if include_data[:prevalent_values]
+            reshash = Hash.new
+            res.each do |row|
+                reshash[row['key']] = row
+                row['prevalent_values'] = Array.new
+            end
+
+            prevvalues = @db.select('SELECT key, value, count, fraction FROM db.prevalent_values').
+                condition("key IN (#{ res.map{ |row| "'" + SQLite3::Database.quote(row['key']) + "'" }.join(',') })").
+                order_by([:count], 'DESC').
+                execute()
+
+            prevvalues.each do |pv|
+                key = pv['key']
+                pv.delete_if{ |k,v| k.is_a?(Integer) || k == 'key' }
+                pv['count'] = pv['count'].to_i
+                pv['fraction'] = pv['fraction'].to_f
+                reshash[key]['prevalent_values'] << pv
+            end
+        end
+
+        return {
+            :page  => @ap.page,
+            :rp    => @ap.results_per_page,
+            :total => total,
+            :data  => res.map{ |row| h = {
+                :key                      => row['key'],
+                :count_all                => row['count_all'].to_i,
+                :count_all_fraction       => (row['count_all'].to_f / @db.stats('objects')).round_to(4),
+                :count_nodes              => row['count_nodes'].to_i,
+                :count_nodes_fraction     => (row['count_nodes'].to_f / @db.stats('nodes_with_tags')).round_to(4),
+                :count_ways               => row['count_ways'].to_i,
+                :count_ways_fraction      => (row['count_ways'].to_f / @db.stats('ways')).round_to(4),
+                :count_relations          => row['count_relations'].to_i,
+                :count_relations_fraction => (row['count_relations'].to_f / @db.stats('relations')).round_to(4),
+                :values_all               => row['values_all'].to_i,
+                :users_all                => row['users_all'].to_i,
+                :in_wiki                  => row['in_wiki'].to_i     == 1 ? true : false,
+                :in_josm                  => row['in_josm'].to_i     == 1 ? true : false,
+                :in_potlatch              => row['in_potlatch'].to_i == 1 ? true : false,
+            } 
+            h[:wikipages] = row['wikipages'] if row['wikipages']
+            h[:prevalent_values] = row['prevalent_values'][0,10] if row['prevalent_values']
+            h }
+        }.to_json
+    end
+
+    api(4, 'keys/wiki_pages', {
+        :description => 'Get list of wiki pages in different languages for all keys.',
+        :parameters => { :query => 'Only show keys matching this query (substring match, optional).' },
+        :paging => :optional,
+        :sort => %w( key ),
+        :result => {
+            :key  => :STRING, 
+            :lang => "Hash with language codes as keys and values showing what type of wiki page is available"
+        },
+        :example => { :page => 1, :rp => 10, :sortname => 'key', :sortorder => 'asc' },
+        :ui => '/reports/language_comparison_table_for_keys_in_the_wiki'
+    }) do
+        languages = @db.execute('SELECT language FROM wiki.wiki_languages ORDER by language').map do |row|
+            row['language']
+        end
+
+        total = @db.count('wiki.wikipages_keys').
+            condition_if("key LIKE '%' || ? || '%'", params[:query]).
+            get_first_value().to_i
+
+        res = @db.select('SELECT key, langs FROM wiki.wikipages_keys').
+            condition_if("key LIKE '%' || ? || '%'", params[:query]).
+            order_by(@ap.sortname, @ap.sortorder){ |o|
+                o.key
+            }.
+            paging(@ap).
+            execute()
+
+        return {
+            :page  => @ap.page,
+            :rp    => @ap.results_per_page,
+            :total => total,
+            :data  => res.map{ |row|
+                lang_hash = Hash.new
+                row['langs'].split(',').each{ |l|
+                    (lang, status) = l.split(' ', 2)
+                    lang_hash[lang] = status
+                }
+                { :key => row['key'], :lang => lang_hash }
+            }
+        }.to_json
+    end
+
+end
diff --git a/web/lib/api/tag.rb b/web/lib/api/tag.rb
new file mode 100644
index 0000000..a4088c1
--- /dev/null
+++ b/web/lib/api/tag.rb
@@ -0,0 +1,159 @@
+# web/lib/api/tag.rb
+class Taginfo < Sinatra::Base
+
+    api(4, 'tag/stats', {
+        :description => 'Show some database statistics for given tag.',
+        :parameters => {
+            :key => 'Tag key (required).',
+            :value => 'Tag value (required).'
+        },
+        :result => {
+            :type           => :STRING,
+            :count          => :INT,
+            :count_fraction => :FLOAT,
+            :values         => :INT
+        },
+        :example => { :key => 'amenity', :value => 'school' },
+        :ui => '/tags/amenity=school#overview'
+    }) do
+        key = params[:key]
+        value = params[:value]
+        out = []
+
+        # default values
+        ['all', 'nodes', 'ways', 'relations'].each_with_index do |type, n|
+            out[n] = { :type => type, :count => 0, :count_fraction => 0.0 }
+        end
+
+        @db.select('SELECT * FROM db.tags').
+            condition('key = ?', key).
+            condition('value = ?', value).
+            execute() do |row|
+                ['all', 'nodes', 'ways', 'relations'].each_with_index do |type, n|
+                    out[n] = {
+                        :type           => type,
+                        :count          => row['count_'  + type].to_i,
+                        :count_fraction => (row['count_'  + type].to_f / get_total(type)).round_to(4)
+                    }
+                end
+        end
+
+        return {
+            :total => 4,
+            :data => out
+        }.to_json
+    end
+
+    api(4, 'tag/combinations', {
+        :description => 'Find keys and tags that are used together with a given tag.',
+        :parameters => {
+            :key => 'Tag key (required).',
+            :value => 'Tag value (required).',
+            :query => 'Only show results where the other_key or other_value matches this query (substring match, optional).'
+        },
+        :paging => :optional,
+        :filter => {
+            :all       => { :doc => 'No filter.' },
+            :nodes     => { :doc => 'Only values on tags used on nodes.' },
+            :ways      => { :doc => 'Only values on tags used on ways.' },
+            :relations => { :doc => 'Only values on tags used on relations.' }
+        },
+        :sort => %w( together_count other_tag from_fraction ),
+        :result => {
+            :other_key      => :STRING,
+            :other_value    => :STRING,
+            :together_count => :INT,
+            :to_fraction    => :FLOAT,
+            :from_fraction  => :FLOAT
+        },
+        :example => { :key => 'highway', :value => 'residential', :page => 1, :rp => 10, :sortname => 'together_count', :sortorder => 'desc' },
+        :ui => '/tags/highway=residential#combinations'
+    }) do
+        key = params[:key]
+        value = params[:value]
+        filter_type = get_filter()
+
+        if @ap.sortname == 'to_count'
+            @ap.sortname = ['together_count']
+        elsif @ap.sortname == 'from_count'
+            @ap.sortname = ['from_fraction', 'together_count', 'other_key', 'other_value']
+        elsif @ap.sortname == 'other_tag'
+            @ap.sortname = ['other_key', 'other_value']
+        end
+
+        cq = @db.count('db.tagpairs')
+        total = (params[:query].to_s != '' ?
+                cq.condition("(key1=? AND value1=? AND (key2 LIKE '%' || ? || '%' OR value2 LIKE '%' || ? || '%')) OR (key2=? AND value2=? AND (key1 LIKE '%' || ? || '%' OR value2 LIKE '%' || ? || '%'))",
+                    key, value, params[:query], params[:query], key, value, params[:query], params[:query]) :
+                cq.condition('(key1=? AND value1=?) OR (key2=? AND value2=?)', key, value, key, value)).
+            condition("count_#{filter_type} > 0").
+            get_first_value().to_i
+
+        has_this_key = @db.select("SELECT count_#{filter_type} FROM db.tags").
+            condition('key = ?', key).
+            condition('value = ?', value).
+            get_first_value()
+
+        res = (params[:query].to_s != '' ?
+            @db.select("SELECT p.key1 AS other_key, p.value1 AS other_value, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.tagpairs p, db.selected_tags k WHERE p.key1=k.skey AND p.value1=k.svalue AND k.svalue != '' AND p.key2=? AND p.value2=? AND ((p.key1 LIKE '%' || ? || '%') OR (p.value1 LIKE '%' || ? || '%')) AND p.count_#{filter_type} > 0
+                    UNION SELECT p.key1 AS other_key, p.value1 AS other_value, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.tagpairs p, db.keys k WHERE p.key1=k.key AND p.value1='' AND p.key2=? AND p.value2=? AND ((p.key1 LIKE '%' || ? || '%') OR (p.value1 LIKE '%' || ? || '%')) AND p.count_#{filter_type} > 0
+                    UNION SELECT p.key2 AS other_key, p.value2 AS other_value, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.tagpairs p, db.selected_tags k WHERE p.key2=k.skey AND p.value2=k.svalue AND k.svalue != '' AND p.key1=? AND p.value1=? AND ((p.key2 LIKE '%' || ? || '%') OR (p.value2 LIKE '%' || ? || '%')) AND p.count_#{filter_type} > 0
+                    UNION SELECT p.key2 AS other_key, p.value2 AS other_value, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.tagpairs p, db.keys k WHERE p.key2=k.key AND p.value2='' AND p.key1=? AND p.value1=? AND ((p.key2 LIKE '%' || ? || '%') OR (p.value2 LIKE '%' || ? || '%')) AND p.count_#{filter_type} > 0", key, value, params[:query], params[:query], key, value, params[:query], params[:query], key, value, params[:query], params[:query], key, value, params[:query], params[:query]) :
+            @db.select("SELECT p.key1 AS other_key, p.value1 AS other_value, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.tagpairs p, db.selected_tags k WHERE p.key1=k.skey AND p.value1=k.svalue AND k.svalue != '' AND p.key2=? AND p.value2=? AND p.count_#{filter_type} > 0 
+                    UNION SELECT p.key1 AS other_key, '' AS other_value, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.tagpairs p, db.keys k WHERE p.key1=k.key AND p.value1 = '' AND p.key2=? AND p.value2=? AND p.count_#{filter_type} > 0 
+                    UNION SELECT p.key2 AS other_key, p.value2 AS other_value, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.tagpairs p, db.selected_tags k WHERE p.key2=k.skey AND p.value2=k.svalue AND k.svalue != '' AND p.key1=? AND p.value1=? AND p.count_#{filter_type} > 0
+                    UNION SELECT p.key2 AS other_key, '' AS other_value, p.count_#{filter_type} AS together_count, k.count_#{filter_type} AS other_count, CAST(p.count_#{filter_type} AS REAL) / k.count_#{filter_type} AS from_fraction FROM db.tagpairs p, db.keys k WHERE p.key2=k.key AND p.value2 = '' AND p.key1=? AND p.value1=? AND p.count_#{filter_type} > 0", key, value, key, value, key, value, key, value)).
+            order_by(@ap.sortname, @ap.sortorder) { |o|
+                o.together_count
+                o.other_key
+                o.other_value
+                o.from_fraction
+            }.
+            paging(@ap).
+            execute()
+
+        return {
+            :page  => @ap.page,
+            :rp    => @ap.results_per_page,
+            :total => total,
+            :data  => res.map{ |row| {
+                :other_key      => row['other_key'],
+                :other_value    => row['other_value'],
+                :together_count => row['together_count'].to_i,
+                :to_fraction    => (row['together_count'].to_f / has_this_key.to_f).round_to(4),
+                :from_fraction  => row['from_fraction'].to_f.round_to(4)
+            } }
+        }.to_json
+    end
+
+    api(4, 'tag/wiki_pages', {
+        :description => 'Get list of wiki pages in different languages describing a tag.',
+        :parameters => { :key => 'Tag key (required)', :value => 'Tag value (required).' },
+        :paging => :no,
+        :result => {
+            :lang             => :STRING,
+            :language         => :STRING,
+            :language_en      => :STRING,
+            :title            => :STRING,
+            :description      => :STRING,
+            :image            => :STRING,
+            :on_node          => :BOOL,
+            :on_way           => :BOOL,
+            :on_area          => :BOOL,
+            :on_relation      => :BOOL,
+            :tags_implies     => :ARRAY_OF_STRINGS,
+            :tags_combination => :ARRAY_OF_STRINGS,
+            :tags_linked      => :ARRAY_OF_STRINGS
+        },
+        :example => { :key => 'highway', :value => 'residential' },
+        :ui => '/tags/highway=residential#wiki'
+    }) do
+        key   = params[:key]
+        value = params[:value]
+
+        res = @db.execute('SELECT * FROM wikipages WHERE key = ? AND value = ? ORDER BY lang', key, value)
+
+        return get_wiki_result(res)
+    end
+
+end
diff --git a/web/lib/api/tags.rb b/web/lib/api/tags.rb
new file mode 100644
index 0000000..f9b2432
--- /dev/null
+++ b/web/lib/api/tags.rb
@@ -0,0 +1,61 @@
+# web/lib/api/tags.rb
+class Taginfo < Sinatra::Base
+
+    api(4, 'tags/popular', {
+        :description => 'Get list of most often used tags.',
+        :parameters => { :query => 'Only show tags matching this query (substring match in key and value, optional).' },
+        :paging => :optional,
+        :sort => %w( tag count_all count_nodes count_ways count_relations ),
+        :result => {
+            :key                      => :STRING, 
+            :value                    => :STRING, 
+            :count_all                => :INT,
+            :count_all_fraction       => :FLOAT,
+            :count_nodes              => :INT,
+            :count_nodes_fraction     => :FLOAT,
+            :count_ways               => :INT,
+            :count_ways_fraction      => :FLOAT,
+            :count_relations          => :INT,
+            :count_relations_fraction => :FLOAT,
+        },
+        :example => { :page => 1, :rp => 10, :sortname => 'tag', :sortorder => 'asc' },
+        :ui => '/tags'
+    }) do
+
+        total = @db.count('db.selected_tags').
+            condition_if("(skey LIKE '%' || ? || '%') OR (svalue LIKE '%' || ? || '%')", params[:query], params[:query]).
+            get_first_value().to_i
+        
+        res = @db.select('SELECT * FROM db.selected_tags').
+            condition_if("(skey LIKE '%' || ? || '%') OR (svalue LIKE '%' || ? || '%')", params[:query], params[:query]).
+            order_by(@ap.sortname, @ap.sortorder) { |o|
+                o.tag :skey
+                o.tag :svalue
+                o.count_all
+                o.count_nodes
+                o.count_ways
+                o.count_relations
+            }.
+            paging(@ap).
+            execute()
+
+        return {
+            :page  => @ap.page,
+            :rp    => @ap.results_per_page,
+            :total => total,
+            :data  => res.map{ |row| {
+                :key                      => row['skey'],
+                :value                    => row['svalue'],
+                :count_all                => row['count_all'].to_i,
+                :count_all_fraction       => (row['count_all'].to_f / @db.stats('objects')).round_to(4),
+                :count_nodes              => row['count_nodes'].to_i,
+                :count_nodes_fraction     => (row['count_nodes'].to_f / @db.stats('nodes_with_tags')).round_to(4),
+                :count_ways               => row['count_ways'].to_i,
+                :count_ways_fraction      => (row['count_ways'].to_f / @db.stats('ways')).round_to(4),
+                :count_relations          => row['count_relations'].to_i,
+                :count_relations_fraction => (row['count_relations'].to_f / @db.stats('relations')).round_to(4),
+            } }
+        }.to_json
+    end
+
+end
diff --git a/web/lib/api/wiki.rb b/web/lib/api/wiki.rb
index 350147a..6245139 100644
--- a/web/lib/api/wiki.rb
+++ b/web/lib/api/wiki.rb
@@ -1,25 +1,6 @@
 # web/lib/api/wiki.rb
 class Taginfo < Sinatra::Base
 
-    def get_wiki_result(res)
-        return res.map{ |row| {
-                :lang             => h(row['lang']),
-                :language         => h(::Language[row['lang']].native_name),
-                :language_en      => h(::Language[row['lang']].english_name),
-                :title            => h(row['title']),
-                :description      => h(row['description']),
-                :image            => h(row['image']),
-                :on_node          => row['on_node'].to_i     == 1 ? true : false,
-                :on_way           => row['on_way'].to_i      == 1 ? true : false,
-                :on_area          => row['on_area'].to_i     == 1 ? true : false,
-                :on_relation      => row['on_relation'].to_i == 1 ? true : false,
-                :tags_implies     => row['tags_implies'    ].split(','),
-                :tags_combination => row['tags_combination'].split(','),
-                :tags_linked      => row['tags_linked'     ].split(',')
-            }
-        }.to_json
-    end
-
     api(2, 'wiki/keys') do
         key = params[:key]
 
diff --git a/web/lib/utils.rb b/web/lib/utils.rb
index 56a5934..c30ff04 100644
--- a/web/lib/utils.rb
+++ b/web/lib/utils.rb
@@ -176,3 +176,23 @@ def api(version, path, doc=nil, &block)
     get("/api/#{version}/#{path}", &block)
 end
 
+# Used in wiki api calls
+def get_wiki_result(res)
+    return res.map{ |row| {
+            :lang             => h(row['lang']),
+            :language         => h(::Language[row['lang']].native_name),
+            :language_en      => h(::Language[row['lang']].english_name),
+            :title            => h(row['title']),
+            :description      => h(row['description']),
+            :image            => h(row['image']),
+            :on_node          => row['on_node'].to_i     == 1,
+            :on_way           => row['on_way'].to_i      == 1,
+            :on_area          => row['on_area'].to_i     == 1,
+            :on_relation      => row['on_relation'].to_i == 1,
+            :tags_implies     => row['tags_implies'    ].split(','),
+            :tags_combination => row['tags_combination'].split(','),
+            :tags_linked      => row['tags_linked'     ].split(',')
+        }
+    }.to_json
+end
+
diff --git a/web/taginfo.rb b/web/taginfo.rb
index 13bcc2f..b0216d2 100755
--- a/web/taginfo.rb
+++ b/web/taginfo.rb
@@ -196,6 +196,10 @@ class Taginfo < Sinatra::Base
 
     # current API (version 4)
     load 'lib/api/site.rb'
+    load 'lib/api/key.rb'
+    load 'lib/api/keys.rb'
+    load 'lib/api/tag.rb'
+    load 'lib/api/tags.rb'
 
     load 'lib/ui/embed.rb'
     load 'lib/ui/keys_tags.rb'
diff --git a/web/views/taginfo/apidoc.erb b/web/views/taginfo/apidoc.erb
index 864dacc..4988d0d 100644
--- a/web/views/taginfo/apidoc.erb
+++ b/web/views/taginfo/apidoc.erb
@@ -4,14 +4,14 @@
 
 <% if params[:show_deprecated] %>
 <p><span class="button"><a href="/taginfo/apidoc">Do not show deprecated API calls</a></span></p>
+<p style="color: red;">Not all of the older, deprecated API calls are documented!</p>
+
 <% else %>
 <p><span class="button"><a href="/taginfo/apidoc?show_deprecated=true">Also show deprecated API calls</a></span></p>
 <% end %>
 
 <h2>Table of Contents</h2>
 
-<p style="color: red;">This list of API calls and their descriptions are not complete!</p>
-
 <ul>
 <% API.paths.keys.sort.each do |version|
        API.paths[version].keys.sort.each do |path|
diff --git a/web/viewsjs/key.js.erb b/web/viewsjs/key.js.erb
index 5946cd6..744dde7 100644
--- a/web/viewsjs/key.js.erb
+++ b/web/viewsjs/key.js.erb
@@ -6,7 +6,7 @@
 var create_flexigrid_for = {
     overview: function(key, filter_type) {
         create_flexigrid('grid-overview', {
-            url: '/api/3/db/keys/overview?key=' + encodeURIComponent(key),
+            url: '/api/4/key/stats?key=' + encodeURIComponent(key),
             colModel: [
                 { display: '<%= misc.object_type %>', name: 'type', width: 100, sortable: true },
                 { display: '<%= page.number_objects %>', name: 'count', width: 260, sortable: true, align: 'center' },
@@ -18,7 +18,7 @@ var create_flexigrid_for = {
                 return {
                     total: 4,
                     page: 1,
-                    rows: jQuery.map(data, function(row, i) {
+                    rows: jQuery.map(data.data, function(row, i) {
                         return { 'cell': [
                             print_image(row.type) + ' ' + texts.osm[row.type],
                             print_value_with_percent(row.count, row.count_fraction),
@@ -31,7 +31,7 @@ var create_flexigrid_for = {
     },
     values: function(key, filter_type, lang) {
         create_flexigrid('grid-values', {
-            url: '/api/2/db/keys/values?key=' + encodeURIComponent(key) + '&filter=' + encodeURIComponent(filter_type) + '&lang=' + encodeURIComponent(lang),
+            url: '/api/4/key/values?key=' + encodeURIComponent(key) + '&filter=' + encodeURIComponent(filter_type) + '&lang=' + encodeURIComponent(lang),
             colModel: [
                 { display: '<%= osm.value %>', name: 'value', width: 200, sortable: true },
                 { display: '<%= misc.count %>', name: 'count', width: 240, sortable: true, align: 'center' },
@@ -57,7 +57,7 @@ var create_flexigrid_for = {
     },
     combinations: function(key, filter_type) {
         create_flexigrid('grid-keys', {
-            url: '/api/2/db/keys/keys?key=' + encodeURIComponent(key) + '&filter=' + encodeURIComponent(filter_type),
+            url: '/api/4/key/combinations?key=' + encodeURIComponent(key) + '&filter=' + encodeURIComponent(filter_type),
             colModel: [
                 { display: '<span title="<%= page.other_keys_used.to_count_tooltip %>"><%= misc.count %> &rarr;</span>', name: 'to_count', width: 320, sortable: true, align: 'center' },
                 { display: '<span title="<%= page.other_keys_used.other_key_tooltip %>"><%= page.other_keys_used.other %></span>', name: 'other_key', width: 340, sortable: true },
@@ -82,7 +82,7 @@ var create_flexigrid_for = {
     },
     wiki: function(key, filter_type) {
         create_flexigrid('grid-wiki', {
-            url: '/api/2/wiki/keys?key=' + encodeURIComponent(key),
+            url: '/api/4/key/wiki_pages?key=' + encodeURIComponent(key),
             colModel: [
                 { display: '<%= misc.language %>', name: 'lang', width: 150, sortable: false },
                 { display: '<%= page.wiki_pages.wiki_page %>', name: 'title', width: 160, sortable: false, align: 'right' },
diff --git a/web/viewsjs/reports/language_comparison_table_for_keys_in_the_wiki.js.erb b/web/viewsjs/reports/language_comparison_table_for_keys_in_the_wiki.js.erb
index 1ae7e5e..f4f99cd 100644
--- a/web/viewsjs/reports/language_comparison_table_for_keys_in_the_wiki.js.erb
+++ b/web/viewsjs/reports/language_comparison_table_for_keys_in_the_wiki.js.erb
@@ -18,7 +18,7 @@ function page_init() {
     var rp = calculate_flexigrid_rp(jQuery('div.box')) - 1;
     current_grid = 'grid-keys';
     grids[current_grid] = jQuery('#grid-keys').flexigrid({
-        url: '/api/2/wiki/keys',
+        url: '/api/4/keys/wiki_pages',
         method: 'GET',
         dataType: 'json',
         colModel: [
diff --git a/web/viewsjs/tag.js.erb b/web/viewsjs/tag.js.erb
index 8071944..e0fb9f8 100644
--- a/web/viewsjs/tag.js.erb
+++ b/web/viewsjs/tag.js.erb
@@ -6,7 +6,7 @@
 var create_flexigrid_for = {
     overview: function(key, value, filter_type) {
         create_flexigrid('grid-overview', {
-            url: '/api/3/db/tags/overview?key=' + encodeURIComponent(key) + '&value=' + encodeURIComponent(value),
+            url: '/api/4/tag/stats?key=' + encodeURIComponent(key) + '&value=' + encodeURIComponent(value),
             colModel: [
                 { display: '<%= misc.object_type %>', name: 'type', width: 100, sortable: true },
                 { display: '<%= page.number_objects %>', name: 'count', width: 260, sortable: true, align: 'center' }
@@ -17,7 +17,7 @@ var create_flexigrid_for = {
                 return {
                     total: 4,
                     page: 1,
-                    rows: jQuery.map(data, function(row, i) {
+                    rows: jQuery.map(data.data, function(row, i) {
                         return { 'cell': [
                             print_image(row.type) + ' ' + texts.osm[row.type],
                             print_value_with_percent(row.count, row.count_fraction)
@@ -29,7 +29,7 @@ var create_flexigrid_for = {
     },
     combinations: function(key, value, filter_type) {
         create_flexigrid('grid-combinations', {
-            url: '/api/2/db/tags/combinations?key=' + encodeURIComponent(key) + '&value=' + encodeURIComponent(value) + '&filter=' + encodeURIComponent(filter_type),
+            url: '/api/4/tag/combinations?key=' + encodeURIComponent(key) + '&value=' + encodeURIComponent(value) + '&filter=' + encodeURIComponent(filter_type),
             colModel: [
                 { display: '<span title="<%= page.other_tags_used.to_count_tooltip %>"><%= misc.count %> &rarr;</span>', name: 'to_count', width: 320, sortable: true, align: 'center' },
                 { display: '<span title="<%= page.other_tags_used.other_key_tooltip %>"><%= page.other_tags_used.other %></span>', name: 'other_tag', width: 340, sortable: true },
@@ -55,7 +55,7 @@ var create_flexigrid_for = {
     },
     wiki: function(key, value) {
         create_flexigrid('grid-wiki', {
-            url: '/api/2/wiki/tags?key=' + encodeURIComponent(key) + '&value=' + encodeURIComponent(value),
+            url: '/api/4/tag/wiki_pages?key=' + encodeURIComponent(key) + '&value=' + encodeURIComponent(value),
             colModel: [
                 { display: '<%= misc.language %>', name: 'lang', width: 150, sortable: false },
                 { display: '<%= page.wiki_pages.wiki_page %>', name: 'title', width: 200, sortable: false, align: 'right' },