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Diffstat (limited to 'http-client.scm')
| -rw-r--r-- | http-client.scm | 892 |
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diff --git a/http-client.scm b/http-client.scm new file mode 100644 index 0000000..d72ce40 --- /dev/null +++ b/http-client.scm @@ -0,0 +1,892 @@ +;;; +;;; Convenient HTTP client library +;;; +;; Copyright (c) 2008-2018, Peter Bex +;; Parts copyright (c) 2000-2004, Felix L. Winkelmann +;; All rights reserved. +;; +;; Redistribution and use in source and binary forms, with or without +;; modification, are permitted provided that the following conditions +;; are met: +;; +;; 1. Redistributions of source code must retain the above copyright +;; notice, this list of conditions and the following disclaimer. +;; 2. Redistributions in binary form must reproduce the above +;; copyright notice, this list of conditions and the following +;; disclaimer in the documentation and/or other materials provided +;; with the distribution. +;; 3. Neither the name of the author nor the names of its +;; contributors may be used to endorse or promote products derived +;; from this software without specific prior written permission. +;; +;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +;; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +;; FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +;; COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, +;; INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +;; (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +;; SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +;; HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +;; STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +;; ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED +;; OF THE POSSIBILITY OF SUCH DAMAGE. +; +(module http-client + (max-retry-attempts max-redirect-depth max-idle-connections + retry-request? client-software + close-connection! close-idle-connections! + call-with-input-request call-with-input-request* + with-input-from-request call-with-response + store-cookie! delete-cookie! get-cookies-for-uri + http-authenticators get-username/password + basic-authenticator digest-authenticator + determine-username/password determine-proxy + determine-proxy-from-environment determine-proxy-username/password + server-connector default-server-connector + prepare-request default-prepare-request) + +(import scheme + srfi-1 srfi-13 srfi-18 srfi-69 + (chicken base) (chicken string) (chicken time) + (chicken sort) (chicken io) (chicken file posix) (chicken format) + (chicken process-context) (chicken process-context posix) + (chicken port) (chicken file) (chicken tcp) (chicken condition) + (chicken pathname) + intarweb uri-common simple-md5 sendfile) + +;; Major TODOs: +;; * Find a better approach for storing cookies, which does not +;; lead to memory leaks. +;; * Implement md5-sess handling for digest auth +;; * Use nonce count in digest auth (is this even needed? I think it's only +;; needed if there are webservers out there that send the same nonce +;; repeatedly. This client doesn't do request pipelining so we don't +;; generate requests with the same nonce if the server doesn't) +;; * Test and document SSL support +;; * The authenticators stuff is really really ugly. It's intentionally +;; undocumented so nobody is going to rely on it too much yet, and +;; we have the freedom to change it later. + +(define-record http-connection base-uri inport outport proxy) + +(define max-retry-attempts (make-parameter 1)) +(define max-redirect-depth (make-parameter 5)) +;; Total idle connections. Maybe later we'll add per-server limits. +(define max-idle-connections (make-parameter 32)) + +(define retry-request? (make-parameter idempotent?)) + +(define (determine-proxy-from-environment uri) + (let* ((is-cgi-process (get-environment-variable "REQUEST_METHOD")) + ;; If we're running in a CGI script, don't use HTTP_PROXY, to + ;; avoid a "httpoxy" attack. Instead, we use the variable + ;; CGI_HTTP_PROXY. See https://httpoxy.org + (proxy-variable + (if (and (eq? (uri-scheme uri) 'http) is-cgi-process) + "cgi_http_proxy" + (conc (uri-scheme uri) "_proxy"))) + (no-proxy (or (get-environment-variable "no_proxy") + (get-environment-variable "NO_PROXY"))) + (no-proxy (and no-proxy (map (lambda (s) + (string-split s ":")) + (string-split no-proxy ",")))) + (host-excluded? (lambda (entry) + (let ((host (car entry)) + (port (and (pair? (cdr entry)) + (string->number (cadr entry))))) + (and (or (string=? host "*") + (string-ci=? host (uri-host uri))) + (or (not port) + (= (uri-port uri) port))))))) + (cond + ((and no-proxy (any host-excluded? no-proxy)) #f) + ((or (get-environment-variable proxy-variable) + (get-environment-variable (string-upcase proxy-variable)) + (get-environment-variable "all_proxy") + (get-environment-variable "ALL_PROXY")) => + (lambda (proxy) ; TODO: make this just absolute-uri + (and-let* ((proxy-uri (uri-reference proxy)) + ((absolute-uri? proxy-uri))) + proxy-uri))) + (else #f)))) + +(define determine-proxy (make-parameter determine-proxy-from-environment)) + +(define determine-proxy-username/password + (make-parameter (lambda (uri realm) + (values (uri-username uri) (uri-password uri))))) + +;; Maybe only pass uri and realm to this? +(define determine-username/password + (make-parameter (lambda (uri realm) + (values (uri-username uri) (uri-password uri))))) + +(define client-software + (make-parameter (list (list "CHICKEN Scheme HTTP-client" "1.0" #f)))) + + +(define (with-mutex m thunk) + (dynamic-wind + (lambda () (mutex-lock! m)) + thunk + (lambda () (mutex-unlock! m)))) + +;; TODO: find a smarter storage mechanism. Also, this implementation +;; means cookies are shared between threads, which might not (always) +;; be desirable. +(define *cookie-jar* (list)) + +;; A hash table containing uri-host&port as keys. Values are circular +;; lists of connections, pointing to the cons cell of the oldest one. +(define *idle-connections* + (make-hash-table + (lambda (a b) + (and (equal? (uri-port a) (uri-port b)) + (equal? (uri-host a) (uri-host b)))) + (lambda (uri . maybe-bound) + (apply string-hash + (sprintf "~S ~S" (uri-host uri) (uri-port uri)) + maybe-bound)))) + +;; This mutex also stores the connection count. However, it should be +;; locked whenever *idle-connections* is accessed, because another +;; thread should not be able to claim a connection we consider using. +(define *idle-connections-mutex* (make-mutex '*idle-connections*)) +(mutex-specific-set! *idle-connections-mutex* 0) + +(define (connection-dropped? con) + (or (port-closed? (http-connection-inport con)) + (port-closed? (http-connection-outport con)) + (condition-case + (and (char-ready? (http-connection-inport con)) + (eof-object? (peek-char (http-connection-inport con)))) + ;; Assume connection got reset when we get this exception + ((exn i/o net) #t)))) + +;; Remove the first (oldest) idle connection which is still alive from +;; the pool and return it. Any dead connections are pruned. +(define (grab-idle-connection! uri) + (with-mutex + *idle-connections-mutex* + (lambda () + (define (take-first-idle-connection!) + ;; This picks the first idle connection, if any, and removes it + ;; from the list. + (and-let* ((head (hash-table-ref/default *idle-connections* uri #f)) + (connection (car head)) + (next (cdr head)) + (count (mutex-specific *idle-connections-mutex*))) + (if (eq? next head) + (hash-table-delete! *idle-connections* uri) + ;; Rip out the next entry and move its value forward + (begin (set-car! head (car next)) + (set-cdr! head (cdr next)))) + (mutex-specific-set! *idle-connections-mutex* (sub1 count)) + connection)) + + (let lp () + (and-let* ((con (take-first-idle-connection!))) + (cond ((connection-dropped? con) + (close-connection! con) + (lp)) + (else con))))))) + +;; If max-idle-connections is not yet reached, add it to the pool. We +;; add it to the end because it is the freshest one. This ensures +;; we'll re-use the oldest first, trying to keep them all alive. If +;; the maximum is reached, close and discard the connection. +(define (maybe-add-idle-connection! uri con) + (with-mutex + *idle-connections-mutex* + (lambda () + (let ((count (mutex-specific *idle-connections-mutex*))) + (if (< count (max-idle-connections)) + (begin + (cond ((hash-table-ref/default *idle-connections* uri #f) => + (lambda (oldest-con) + (let lp ((head (cdr oldest-con))) + (if (eq? (cdr head) oldest-con) ; last? + (set-cdr! head (cons con oldest-con)) + (lp (cdr head)))))) + (else + (let ((new-con (list con))) + (set-cdr! new-con new-con) ; (circular-list con) + (hash-table-set! *idle-connections* uri new-con)))) + (mutex-specific-set! *idle-connections-mutex* (add1 count))) + (close-connection! con)))))) + + +(define (close-connection! uri-or-con) + (cond ((http-connection? uri-or-con) + (close-input-port (http-connection-inport uri-or-con)) + (close-output-port (http-connection-outport uri-or-con))) + ((grab-idle-connection! uri-or-con) => + (lambda (con) + (close-connection! con) ; Close this one + (close-connection! uri-or-con))))) ; Check for others + + +(define (close-idle-connections!) + (with-mutex + *idle-connections-mutex* + (lambda () + (hash-table-walk + *idle-connections* + (lambda (uri conns) + (let lp ((to-close (cdr conns))) + (unless (eq? to-close conns) + (close-input-port (http-connection-inport (car to-close))) + (close-output-port (http-connection-outport (car to-close))) + (lp (cdr to-close)))) + (hash-table-delete! *idle-connections* uri))) + (mutex-specific-set! *idle-connections-mutex* 0)))) + +;; Imports from the openssl egg, if available +(define (dynamic-import module symbol default) + (handle-exceptions _ default (eval `(let () (import ,module) ,symbol)))) + +(define ssl-connect* + (dynamic-import 'openssl 'ssl-connect* (lambda _ (values #f #f)))) + +(define (default-server-connector uri proxy) + (let ((remote-end (or proxy uri))) + (case (uri-scheme remote-end) + ((#f http) (tcp-connect (uri-host remote-end) (uri-port remote-end))) + ((https) (receive (in out) + (ssl-connect* hostname: (uri-host remote-end) + port: (uri-port remote-end) + sni-name: #t) + (if (and in out) ; Ugly, but necessary + (values in out) + (http-client-error + 'ssl-connect + (conc "Unable to connect over HTTPS. To fix this, " + "install the openssl egg and try again") + (list (uri->string uri)) + 'missing-openssl-egg + 'request-uri uri 'proxy proxy)))) + (else (http-client-error 'ensure-connection! + "Unknown URI scheme" + (list (uri-scheme remote-end)) + 'unsupported-uri-scheme + 'uri-scheme (uri-scheme remote-end) + 'request-uri uri 'proxy proxy))))) + +(define server-connector (make-parameter default-server-connector)) + +(define (ensure-connection! uri) + (or (grab-idle-connection! uri) + (let ((proxy ((determine-proxy) uri))) + (receive (in out) ((server-connector) uri proxy) + (make-http-connection uri in out proxy))))) + +(define (make-delimited-input-port port len) + (if (not len) + port ;; no need to delimit anything + (let ((pos 0)) + (make-input-port + (lambda () ; read-char + (if (= pos len) + #!eof + (let ((char (read-char port))) + (set! pos (add1 pos)) + char))) + (lambda () ; char-ready? + (or (= pos len) (char-ready? port))) + (lambda () ; close + (close-input-port port)) + (lambda () ; peek-char + (if (= pos len) + #!eof + (peek-char port))) + (lambda (p bytes buf off) ; read-string! + (let* ((bytes (min bytes (- len pos))) + (bytes-read (read-string! bytes buf port off))) + (set! pos (+ pos bytes-read)) + bytes-read)) + (lambda (p limit) ; read-line + (if (= pos len) + #!eof + (let* ((bytes-left (- len pos)) + (limit (min (or limit bytes-left) bytes-left)) + (line (read-line port limit))) + (unless (eof-object? line) + (set! pos (+ pos (string-length line)))) + line))))))) + +(define discard-remaining-data! + (let ((buf (make-string 1024))) ; Doesn't matter, discarded anyway + (lambda (response port) + ;; If header not available or no response object passed, this reads until EOF + (let loop ((len (and response + (header-value + 'content-length (response-headers response))))) + (if len + (when (> len 0) + (loop (- len (read-string! len buf port)))) + (when (> (read-string! (string-length buf) buf port) 0) + (loop #f))))))) + +(define (default-prepare-request req) + (let* ((uri (request-uri req)) + (cookies (get-cookies-for-uri (request-uri req))) + (h `(,@(if (not (null? cookies)) `((cookie . ,cookies)) '()) + ,@(if (and (client-software) (not (null? (client-software)))) + `((user-agent ,(client-software))) + '())))) + (update-request req + headers: (headers h (request-headers req))))) + +(define prepare-request (make-parameter default-prepare-request)) + +(define (http-client-error loc msg args specific . rest) + (raise (make-composite-condition + (make-property-condition 'exn 'location loc 'message msg 'arguments args) + (make-property-condition 'http) + (apply make-property-condition specific rest)))) + +;; RFC 2965, section 3.3.3 +(define (cookie-eq? a-name a-info b-name b-info) + (and (string-ci=? a-name b-name) + (string-ci=? (alist-ref 'domain a-info) (alist-ref 'domain b-info)) + (equal? (alist-ref 'path a-info) (alist-ref 'path b-info)))) + +(define (store-cookie! cookie-info set-cookie) + (let loop ((cookie (set-cookie->cookie set-cookie)) + (jar *cookie-jar*)) + (cond + ((null? jar) + (set! *cookie-jar* (cons (cons cookie-info cookie) *cookie-jar*)) + *cookie-jar*) + ((cookie-eq? (car (get-value set-cookie)) cookie-info + (car (get-value (cdar jar))) (caar jar)) + (set-car! jar (cons cookie-info cookie)) + *cookie-jar*) + (else (loop cookie (cdr jar)))))) + +(define (delete-cookie! cookie-name cookie-info) + (set! *cookie-jar* + (remove! (lambda (c) + (cookie-eq? (car (get-value (cdr c))) (car c) + cookie-name cookie-info)) + *cookie-jar*))) + +(define (domain-match? uri pattern) + (let ((target (uri-host uri))) + (or (string-ci=? target pattern) + (and (string-prefix? "." pattern) + (string-suffix-ci? pattern target))))) + +(define (path-match? uri path) + (and (uri-path-absolute? uri) + (let loop ((path (cdr (uri-path path))) + (uri-path (cdr (uri-path uri)))) + (or (null? path) ; done + (and (not (null? uri-path)) + (or (and (string-null? (car path)) (null? (cdr path))) + + (and (string=? (car path) (car uri-path)) + (loop (cdr path) (cdr uri-path))))))))) + +;; Set-cookie provides some info we don't need to store; strip the +;; nonessential info +(define (set-cookie->cookie info) + (vector (get-value info) + (filter (lambda (p) + (member (car p) '(domain path version))) + (get-params info)))) + +(define (get-cookies-for-uri uri) + (let ((uri (if (string? uri) (uri-reference uri) uri))) + (map cdr + (sort! + (filter (lambda (c) + (let ((info (car c))) + (and (domain-match? uri (alist-ref 'domain info)) + (member (uri-port uri) + (alist-ref 'port info eq? + (list (uri-port uri)))) + (path-match? uri (alist-ref 'path info)) + (if (alist-ref 'secure info) + (member (uri-scheme uri) '(https shttp)) + #t)))) + *cookie-jar*) + (lambda (a b) + (< (length (uri-path (alist-ref 'path (car a)))) + (length (uri-path (alist-ref 'path (car b)))))))))) + +(define (process-set-cookie! con uri r) + (let ((prefix-contains-dots? + (lambda (host pattern) + (string-index host #\. 0 (string-contains-ci host pattern))))) + (for-each (lambda (c) + (and-let* ((path (or (get-param 'path c) uri)) + ((path-match? uri path)) + ;; domain must start with dot. Add to intarweb! + (dn (get-param 'domain c (uri-host uri))) + (idx (string-index dn #\.)) + ((domain-match? uri dn)) + ((not (prefix-contains-dots? (uri-host uri) dn)))) + (store-cookie! `((path . ,path) + (domain . ,dn) + (secure . ,(get-param 'secure c))) c))) + (header-contents 'set-cookie (response-headers r) '())) + (for-each (lambda (c) + (and-let* (((get-param 'version c)) ; required for set-cookie2 + (path (or (get-param 'path c) uri)) + ((path-match? uri path)) + (dn (get-param 'domain c (uri-host uri))) + ((or (string-ci=? dn ".local") + (and (not (string-null? dn)) + (string-index dn #\. 1)))) + ((domain-match? uri dn)) + ((not (prefix-contains-dots? (uri-host uri) dn))) + ;; This is a little bit too messy for my tastes... + ;; Can't use #f because that would shortcut and-let* + (ports-value (get-param 'port c 'any)) + (ports (if (eq? ports-value #t) + (list (uri-port uri)) + ports-value)) + ((or (eq? ports 'any) + (member (uri-port uri) ports)))) + (store-cookie! `((path . ,path) + (domain . ,dn) + (port . ,(if (eq? ports 'any) #f ports)) + (secure . ,(get-param 'secure c))) c))) + (header-contents 'set-cookie2 (response-headers r) '())))) + +(define (get-username/password for-request-header for-uri for-realm) + (if (eq? for-request-header 'authorization) + ((determine-username/password) for-uri for-realm) + ((determine-proxy-username/password) for-uri for-realm))) + +;;; TODO: We really, really should get rid of "writer" here. Some kind of +;;; generalized way to get the digest is required. Jeez, HTTP sucks :( +(define (basic-authenticator response response-header + new-request request-header uri realm writer) + (receive (username password) + (get-username/password request-header uri realm) + (and username + (update-request + new-request + headers: (headers `((,request-header + #(basic ((username . ,username) + (password . ,(or password "")))))) + (request-headers new-request)))))) + +(define (digest-authenticator response response-header + new-request request-header uri realm writer) + (receive (username password) + (get-username/password request-header uri realm) + (and username + (let* ((hashconc + (lambda args + (string->md5sum (string-join (map ->string args) ":")))) + (authless-uri (update-uri (request-uri new-request) + username: #f password: #f)) + ;; TODO: domain handling + (h (response-headers response)) + (nonce (header-param 'nonce response-header h)) + (opaque (header-param 'opaque response-header h)) + (stale (header-param 'stale response-header h)) + ;; TODO: "md5-sess" algorithm handling + (algorithm (header-param 'algorithm response-header h)) + (qops (header-param 'qop response-header h '())) + (qop (cond ; Pick the strongest of the offered options + ((member 'auth-int qops) 'auth-int) + ((member 'auth qops) 'auth) + (else #f))) + (cnonce (and qop (hashconc (current-seconds) realm))) + (nc (and qop 1)) ;; TODO + (ha1 (hashconc username realm (or password ""))) + (ha2 (if (eq? qop 'auth-int) + (hashconc (request-method new-request) + (uri->string authless-uri) + ;; Generate digest from writer's output + ;; TODO: This should not generate one + ;; large string but use a custom port. + ;; Ideally we extract this from + ;; this egg into another one. + (string->md5sum + (call-with-output-string + (lambda (p) + (writer + (update-request new-request port: p)))))) + (hashconc (request-method new-request) + (uri->string authless-uri)))) + (digest + (case qop + ((auth-int auth) + (let ((hex-nc (string-pad (number->string nc 16) 8 #\0))) + (hashconc ha1 nonce hex-nc cnonce qop ha2))) + (else + (hashconc ha1 nonce ha2))))) + (update-request new-request + headers: (headers + `((,request-header + #(digest ((username . ,username) + (uri . ,authless-uri) + (realm . ,realm) + (nonce . ,nonce) + (cnonce . ,cnonce) + (qop . ,qop) + (nc . ,nc) + (response . ,digest) + (opaque . ,opaque))))) + (request-headers new-request))))))) + +(define http-authenticators + (make-parameter `((basic . ,basic-authenticator) + (digest . ,digest-authenticator)))) + +(define (authenticate-request request response writer proxy-uri) + (and-let* ((type (if (= (response-code response) 401) 'auth 'proxy)) + (resp-header (if (eq? type 'auth) + 'www-authenticate + 'proxy-authenticate)) + (req-header (if (eq? type 'auth) + 'authorization + 'proxy-authorization)) + (authtype (header-value resp-header (response-headers response))) + (realm (header-param 'realm resp-header (response-headers response))) + (auth-uri (if (eq? type 'auth) (request-uri request) proxy-uri)) + (authenticator (or (alist-ref authtype (http-authenticators)) + ;; Should we really raise an error? + (http-client-error 'authenticate-request + "Unknown authentication type" + (list authtype) + 'unknown-authtype + 'authtype authtype + 'request request)))) + (authenticator response resp-header request req-header + auth-uri realm writer))) + +(define (call-with-response req writer reader) + (let loop ((attempts 0) + (redirects 0) + (req req)) + (let* ((uri (request-uri req)) + (con (ensure-connection! uri))) + (condition-case + (let* ((req ((prepare-request) + (update-request + req + headers: (headers + `((host ,(cons (uri-host uri) + (and (not (uri-default-port? uri)) + (uri-port uri))))) + (request-headers req)) + port: (http-connection-outport con)))) + ;; No outgoing URIs should ever contain credentials or fragments + (req-uri (update-uri uri fragment: #f username: #f password: #f)) + ;; RFC1945, 5.1.2: "The absoluteURI form is only allowed + ;; when the request is being made to a proxy." + ;; RFC2616 is a little more regular (hosts MUST accept + ;; absoluteURI), but it says "HTTP/1.1 clients will only + ;; generate them in requests to proxies." (also 5.1.2) + (req-uri (if (http-connection-proxy con) + req-uri + (update-uri req-uri + host: #f port: #f scheme: #f))) + ;; Update path only when it needs to be updated, to + ;; avoid unnecessarily mangling it (see #1448) + (req-uri (if (or (http-connection-proxy con) + (not (memq (uri-path req-uri) '(() #f)))) + req-uri + (update-uri req-uri path: '(/ "")))) + (request (write-request (update-request req uri: req-uri))) + ;; Writer should be prepared to be called several times + ;; Maybe try and figure out a good way to use the + ;; "Expect: 100-continue" header to prevent too much writing? + ;; Unfortunately RFC2616 says it's unreliable (8.2.3)... + ;; + ;; TODO: Should we avoid calling "writer" if + ;; request-has-message-body? returns false? + (_ (begin (writer request) + (flush-output (request-port req)) + ;; Signal end of file when we can. + (unless (keep-alive? request) + (close-output-port + (http-connection-outport con))))) + (response (read-response (http-connection-inport con))) + (cleanup! + (lambda (clear-response-data?) + (when clear-response-data? + (discard-remaining-data! response + (response-port response))) + (if (and (keep-alive? request) + (keep-alive? response)) + (maybe-add-idle-connection! uri con) + (close-connection! con))))) + (when response (process-set-cookie! con uri response)) + (case (and response (response-code response)) + ((#f) + ;; If the connection is closed prematurely, we SHOULD + ;; retry, according to RFC2616, section 8.2.4. Currently + ;; don't do "binary exponential backoff", which we MAY do. + (if (and (or (not (max-retry-attempts)) ; unlimited? + (< attempts (max-retry-attempts))) + ((retry-request?) req)) + (loop (add1 attempts) redirects req) + (http-client-error 'send-request + "Server closed connection before sending response" + (list (uri->string uri)) + 'premature-disconnection + 'uri uri 'request req))) + ;; TODO: According to spec, we should provide the user + ;; with a choice when it's not a GET or HEAD request... + ((301 302 303 307) + (cleanup! #t) + ;; Maybe we should switch to GET on 302 too? It's not compliant, + ;; but very widespread and there's enough software that depends + ;; on that behaviour, which might break horribly otherwise... + (when (= (response-code response) 303) + (request-method-set! req 'GET) ; Switch to GET + ;; Is this OK, or avoid calling writer (see above)? + (let ((h (headers '((content-length 0)) + (request-headers req)))) + (request-headers-set! req h)) + (set! writer (lambda x void))) + (let* ((loc-uri (header-value 'location + (response-headers response))) + (new-uri (uri-relative-to loc-uri uri))) + (if (or (not (max-redirect-depth)) ; unlimited? + (< redirects (max-redirect-depth))) + (loop attempts + (add1 redirects) + (update-request req uri: new-uri)) + (http-client-error 'send-request + "Maximum number of redirects exceeded" + (list (uri->string uri)) + 'redirect-depth-exceeded + 'uri uri 'new-uri new-uri + 'request req)))) + ;; TODO: Test this + ((305) ; Use proxy (for this request only) + (cleanup! #t) + (let ((old-determine-proxy (determine-proxy)) + (proxy-uri (header-value 'location (response-headers response)))) + (parameterize ((determine-proxy + (lambda _ + ;; Reset determine-proxy so the proxy is really + ;; used for only this one request. + ;; Yes, this is a bit of a hack :) + (determine-proxy old-determine-proxy) + proxy-uri))) + (loop attempts redirects req)))) + ((401 407) ; Unauthorized, Proxy Authentication Required + (cond ((and (or (not (max-retry-attempts)) ; unlimited? + (< attempts (max-retry-attempts))) + (authenticate-request req response writer + (http-connection-proxy con))) + => (lambda (new-req) + (cleanup! #t) + (loop (add1 attempts) redirects new-req))) + (else ;; pass it on, we can't throw an error here + (let ((data (reader response))) + (values data uri response))))) + (else (let ((data (reader response))) + (cleanup! #f) + (values data uri response))))) + (exn (exn i/o net) + ;; Try to recover from bad connections if we may retry. + (close-connection! con) + (if (and (or (not (max-retry-attempts)) ; unlimited? + (< attempts (max-retry-attempts))) + ((retry-request?) req)) + (loop (add1 attempts) redirects req) + (raise exn))) + (exn () + ;; Never leave the port in an unknown/inconsistent state + ;; (the error could have occurred while reading, so there + ;; might be data left in the buffer) + (close-connection! con) + (raise exn)))))) + +(define (kv-ref l k #!optional default) + (let ((rest (and (pair? l) (memq k l)))) + (if (and rest (pair? (cdr rest))) (cadr rest) default))) + +;; This really, really sucks +;; TODO: This crap probably belongs in its own egg? Perhaps later when +;; we have server-side handling for this too. +(define (prepare-multipart-chunks boundary entries) + (append + (map (lambda (entry) + (if (not (cdr entry)) ; discard #f values + '() + (let* ((keys (cdr entry)) + (file (kv-ref keys file:)) + (filename (or (kv-ref keys filename:) + (and (port? file) (port-name file)) + (and (string? file) file))) + (filename (and filename + (pathname-strip-directory filename))) + (h (headers `((content-disposition + #(form-data ((name . ,(car entry)) + (filename . ,filename)))) + ,@(if filename + '((content-type application/octet-stream)) + '())))) + (hs (call-with-output-string + (lambda (s) + (unparse-headers + ;; Allow user headers to override ours + (headers (kv-ref keys headers: '()) h) s))))) + (list "--" boundary "\r\n" hs "\r\n" + (cond ((string? file) (cons 'file file)) + ((port? file) (cons 'port file)) + ((eq? keys #t) "") + (else (->string keys))) + ;; The next boundary must always start on a new line + "\r\n")))) + entries) + (list (list "--" boundary "--\r\n")))) + +(define (write-chunks output-port entries) + (for-each (lambda (entry) + (for-each (lambda (chunk) + (if (pair? chunk) + (let ((p (if (eq? 'file (car chunk)) + (open-input-file (cdr chunk)) + ;; Should be a port otherwise + (cdr chunk)))) + (handle-exceptions exn + (begin (close-input-port p) (raise exn)) + (sendfile p output-port)) + (close-input-port p)) + (display chunk output-port))) + entry)) + entries)) + +(define (calculate-chunk-size entries) + (call/cc + (lambda (return) + (fold (lambda (chunks total-size) + (fold (lambda (chunk total-size) + (if (pair? chunk) + (if (eq? 'port (car chunk)) + ;; Should be a file otherwise. + ;; We can't calculate port lengths. + ;; Let's just punt and hope the server + ;; won't return "411 Length Required"... + ;; (TODO: maybe try seeking it?) + (return #f) + (+ total-size (file-size (cdr chunk)))) + (+ total-size (string-length chunk)))) + total-size + chunks)) + 0 entries)))) + +(define (call-with-input-request* uri-or-request writer reader) + (let* ((type-headers '()) + (uri (cond ((uri-reference? uri-or-request) uri-or-request) + ((string? uri-or-request) (uri-reference uri-or-request)) + ((request? uri-or-request) (request-uri uri-or-request)) + (else #f))) + (_ (unless (uri? uri) + (http-client-error + 'call-with-input-request + (if (uri-reference? uri) + "Bad argument: URI must be a proper URI, not a relative reference (protocol and host must be set)" + "The first argument must be either an uri-common object, an intarweb request object, or an URI string") + (list uri-or-request writer reader) + 'bad-uri 'uri uri-or-request))) + (req (if (request? uri-or-request) + uri-or-request + (make-request uri: uri method: (if writer 'POST 'GET)))) + (chunks (cond + ((string? writer) (list (list writer))) + ((and (list? writer) + (any (lambda (x) + (and (pair? x) (pair? (cdr x)) + (eq? (cadr x) file:))) + writer)) + (let ((bd (conc "----------------Multipart-=_" + (gensym 'boundary) "=_=" (current-process-id) + "=-=" (current-seconds)))) + (set! type-headers `((content-type #(multipart/form-data ((boundary . ,bd)))))) + (prepare-multipart-chunks bd writer))) + ;; Default to "&" because some servers choke on ";" + ((list? writer) + (set! type-headers + '((content-type application/x-www-form-urlencoded))) + (list (list (or (form-urlencode writer separator: "&") + (http-client-error + 'call-with-input-request + "Invalid form data!" + (list (uri->string uri) writer reader) + 'form-data-error + 'request req + 'form-data writer))))) + (else #f))) + ;; If the size is known, the user can supply a content-length + ;; header to avoid chunking. For HTTP/1.0 we never chunk. + (need-chunked-encoding? + (and (= 1 (request-major req)) (= 1 (request-minor req)) + (not (header-value 'content-length (request-headers req))))) + (size-headers + (cond + (chunks + (let ((size (calculate-chunk-size chunks))) + (cond + (size `((content-length ,size))) + (need-chunked-encoding? `((transfer-encoding chunked))) + (else '())))) + ;; We can't calculate the size except by + ;; calling the procedure, but that's wasteful. + ((and need-chunked-encoding? (procedure? writer)) + `((transfer-encoding chunked))) + (else '()))) + (req (update-request + req headers: (headers `(,@size-headers ,@type-headers) + (request-headers req))))) + (call-with-response + req + (cond (chunks (lambda (r) + (write-chunks (request-port r) chunks) + (finish-request-body r))) + ((procedure? writer) + (lambda (r) + (writer (request-port r)) + (finish-request-body r))) + (else (lambda x (void)))) + (lambda (response) + (let ((port (make-delimited-input-port + (response-port response) + (header-value 'content-length (response-headers response)))) + (body? ((response-has-message-body-for-request?) response req))) + (if (= 200 (response-class response)) ; Everything cool? + (let ((result (and body? reader (reader port response)))) + (when body? (discard-remaining-data! #f port)) + result) + (http-client-error + 'call-with-input-request + ;; Message + (sprintf (case (response-class response) + ((400) "Client error: ~A ~A") + ((500) "Server error: ~A ~A") + (else "Unexpected server response: ~A ~A")) + (response-code response) (response-reason response)) + ;; arguments + (list (uri->string uri)) + ;; Specific type + (case (response-class response) + ((400) 'client-error) + ((500) 'server-error) + (else 'unexpected-server-response)) + 'response response + 'body (and body? (read-string #f port))))))))) + +(define (call-with-input-request uri-or-request writer reader) + (call-with-input-request* uri-or-request writer (lambda (p r) (reader p)))) + +(define (with-input-from-request uri-or-request writer reader) + (call-with-input-request uri-or-request + (if (procedure? writer) + (lambda (p) (with-output-to-port p writer)) + writer) ;; Assume it's an alist or #f + (lambda (p) (with-input-from-port p reader)))) + +) |