From 4e39ac9a9e34680cb4a2e23fe5d7efa21eb9ddec Mon Sep 17 00:00:00 2001 From: Christopher Baines Date: Thu, 25 Mar 2021 10:35:45 +0000 Subject: guix: http-client: Refactor http-multiple-get. Split the procedure in to three smaller procedures, rather than using two longer let statements. This might make it easier to read. * guix/http-client.scm (http-multiple-get): Refactor. --- guix/http-client.scm | 195 ++++++++++++++++++++++++++------------------------- 1 file changed, 101 insertions(+), 94 deletions(-) diff --git a/guix/http-client.scm b/guix/http-client.scm index adbfbc0d6e..b584feba5d 100644 --- a/guix/http-client.scm +++ b/guix/http-client.scm @@ -147,7 +147,7 @@ Raise an '&http-get-error' condition if downloading fails." (uri->string uri) code (response-reason-phrase resp)))))))))))) -(define* (http-multiple-get base-uri proc seed requests +(define* (http-multiple-get base-uri proc seed all-requests #:key port (verify-certificate? #t) (open-connection guix:open-connection-for-uri) (keep-alive? #t) @@ -161,16 +161,90 @@ When PORT is specified, use it as the initial connection on which HTTP requests are sent; otherwise call OPEN-CONNECTION to open a new connection for a URI. When KEEP-ALIVE? is false, close the connection port before returning." - (let connect ((port port) - (requests requests) - (result seed)) + (define (send-batch-of-requests p batch) + ;; Send BATCH in a row. + ;; XXX: Do our own caching to work around inefficiencies when + ;; communicating over TLS: . + (let-values (((buffer get) (open-bytevector-output-port))) + ;; Inherit the HTTP proxying property from P. + (set-http-proxy-port?! buffer (http-proxy-port? p)) + + (for-each (cut write-request <> buffer) + batch) + (put-bytevector p (get)) + (force-output p))) + + (define (process-batch-of-responses p + all-remaining-requests + batch-remaining-requests + processed + result) + (if (null? batch-remaining-requests) + (match (drop all-remaining-requests processed) + (() + (unless keep-alive? + (close-port p)) + (reverse result)) + (remainder + (connect-and-make-requests p remainder result))) + (match + (catch #t + (lambda () + (let* ((request (car batch-remaining-requests)) + (resp (read-response p)) + (body (response-body-port resp)) + (result (proc request resp body result))) + ;; The server can choose to stop responding at any time, in + ;; which case we have to try again. Check whether that is + ;; the case. Note that even upon "Connection: close", we can + ;; read from BODY. + (match (assq 'connection (response-headers resp)) + (('connection 'close) + (close-port p) + (list 'connect-and-make-requests + #f + (drop all-remaining-requests (+ 1 processed)) + result)) + (_ + (list 'process-batch-of-responses + p + all-remaining-requests + (cdr batch-remaining-requests) + (+ 1 processed) + result))))) + (lambda (key . args) + ;; If PORT was cached and the server closed the connection in + ;; the meantime, we get EPIPE. In that case, open a fresh + ;; connection and retry. We might also get 'bad-response or a + ;; similar exception from (web response) later on, once we've + ;; sent the request, or a ERROR/INVALID-SESSION from GnuTLS. + (if (or (and (eq? key 'system-error) + (= EPIPE (system-error-errno `(,key ,@args)))) + (and (eq? key 'gnutls-error) + (eq? (first args) error/invalid-session)) + (memq key + '(bad-response + bad-header + bad-header-component))) + (begin + (close-port p) + (list 'connect-and-make-requests + #f + (drop all-remaining-requests processed) + result)) + (apply throw key args)))) + + (('connect-and-make-requests . args) + (apply connect-and-make-requests args)) + (('process-batch-of-responses . args) + (apply process-batch-of-responses args))))) + + (define (connect-and-make-requests port remaining-requests result) (define batch - (if (>= batch-size (length requests)) - requests - (take requests batch-size))) + (if (>= batch-size (length remaining-requests)) + remaining-requests + (take remaining-requests batch-size))) - ;; (format (current-error-port) "connecting (~a requests left)..." - ;; (length requests)) (let ((p (or port (open-connection base-uri #:verify-certificate? verify-certificate?)))) @@ -178,92 +252,25 @@ returning." (when (file-port? p) (setvbuf p 'block (expt 2 16))) - ;; Send BATCH in a row. - ;; XXX: Do our own caching to work around inefficiencies when - ;; communicating over TLS: . - (let-values (((buffer get) (open-bytevector-output-port))) - ;; Inherit the HTTP proxying property from P. - (set-http-proxy-port?! buffer (http-proxy-port? p)) - - (catch #t - (lambda () - (for-each (cut write-request <> buffer) - batch) - (put-bytevector p (get)) - (force-output p)) - (lambda (key . args) - ;; If PORT becomes unusable, open a fresh connection and - ;; retry. - (if (or (and (eq? key 'system-error) - (= EPIPE (system-error-errno `(,key ,@args)))) - (and (eq? key 'gnutls-error) - (eq? (first args) error/invalid-session))) - (begin - (close-port p) ; close the broken port - (connect #f - requests - result)) - (apply throw key args))))) + (catch #t + (lambda () + (send-batch-of-requests p batch)) + (lambda (key . args) + ;; If PORT becomes unusable, open a fresh connection and retry. + (if (or (and (eq? key 'system-error) + (= EPIPE (system-error-errno `(,key ,@args)))) + (and (eq? key 'gnutls-error) + (eq? (first args) error/invalid-session))) + (begin + (close-port p) ; close the broken port + (connect-and-make-requests #f + remaining-requests + result)) + (apply throw key args)))) - ;; Now start processing responses. - (let loop ((sent batch) - (processed 0) - (result result)) - (match sent - (() - (match (drop requests processed) - (() - (unless keep-alive? - (close-port p)) - (reverse result)) - (remainder - (connect p remainder result)))) - ((head tail ...) - (match - (catch #t - (lambda () - (let* ((resp (read-response p)) - (body (response-body-port resp)) - (result (proc head resp body result))) - ;; The server can choose to stop responding at any time, - ;; in which case we have to try again. Check whether - ;; that is the case. Note that even upon "Connection: - ;; close", we can read from BODY. - (match (assq 'connection (response-headers resp)) - (('connection 'close) - (close-port p) - (list 'connect - #f - (drop requests (+ 1 processed)) - result)) - (_ - (list 'loop tail (+ 1 processed) result))))) - (lambda (key . args) - ;; If PORT was cached and the server closed the connection - ;; in the meantime, we get EPIPE. In that case, open a - ;; fresh connection and retry. We might also get - ;; 'bad-response or a similar exception from (web response) - ;; later on, once we've sent the request, or a - ;; ERROR/INVALID-SESSION from GnuTLS. - (if (or (and (eq? key 'system-error) - (= EPIPE (system-error-errno `(,key ,@args)))) - (and (eq? key 'gnutls-error) - (eq? (first args) error/invalid-session)) - (memq key - '(bad-response - bad-header - bad-header-component))) - (begin - (close-port p) - (list 'connect - #f - (drop requests processed) - result)) - (apply throw key args)))) - (('connect . args) - (apply connect args)) - (('loop . args) - (apply loop args))))))))) + (process-batch-of-responses p remaining-requests batch 0 result))) + + (connect-and-make-requests port all-requests seed)) ;;; -- cgit v1.2.3