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Http-client is a highlevel HTTP client library.
This egg is still under development; the API might change a bit in future versions.
Main request procedures[procedure] (call-with-response request writer reader)
This is the core http-client procedure. It is only necessary to use this when you want the most control over the request/response cycle. request is the request object that contains information about the request to perform. reader is a procedure that receives the response object and should read the request body, writer is a procedure that receives the request object and should write the request body.
The writer should be prepared to be called several times; if the response is a redirect or some other status that indicates the server wants the client to perform a new request, the writer should be ready to write a request body for this new request. In case digest authentication with message integrity checking is used, writer is always invoked at least twice, once to determine the message digest of the response and once to actually write the response.
Returns three values: The result of the call to reader, the request-uri of the last request and the response object. The request-uri is useful because this is to be used as the base uri of the document. This can differ from the initial request in the presence of redirects.[procedure] (call-with-input-request uri-or-request writer reader)
This procedure is a convenience wrapper around call-with-response.
It is much less strict - uri-or-request can be an intarweb request object, but also an uri-common object or even a string with the URI in it, in which case a request object will be automatically constructed around the URI, using the GET method.
writer can be either #f (in which case nothing is written), a string containing the raw data to send, an alist (in which case the data is written out as using www-form-urlencoding, useful for POST requests), or a procedure that accepts a port and writes the response data to it. If you supply a procedure, do not forget to set the content-length header! In the other cases, the length is calculated and the header automatically set for you. If you supplied an alist, the content-type header is automatically set to application/x-www-form-urlencoded.
reader is a procedure which accepts a port and reads out the data.
Returns three values: The result of the call to reader, the request-uri of the last request and the response object. If the response code is not in the 200 class, it will throw an exception of type (exn http client-error), (exn http server-error) or (exn http unexpected-server-response), depending on the response code. This includes 404 not found (which is a client-error).[procedure] (with-input-from-request uri-or-request write-thunk read-thunk)
Same as call-with-input-request, except this accepts thunks (lambdas of no arguments) which will be executed with the current input (or output) port to the request or response port, respectively.
(use http-client) (with-input-from-request "http://wiki.call-cc.org/" #f read-string) => ;; [the chicken wiki page HTML contents] (use http-client uri-common intarweb) ;; Perform a POST of the key "test" with value "value" to an echo service (with-input-from-request (make-request method: 'POST uri: (uri-reference "http://localhost/echo-service")) '((test . "value")) read-string) => "You posted: test=value"
Parameters[parameter] (max-retry-attempts [number])
When a request fails because of an I/O or network problem (or simply because the remote end closed a persistent connection while we were doing something else), the library will try to establish a new connection and perform the request again. This parameter controls how many times this is allowed to be done. If #f, it will never give up.
Defaults to 1.[parameter] (retry-request? [predicate])
This procedure is invoked when a retry should take place, to determine if it should take place at all. It should be a procedure accepting a request object and returning #f or a true value. If the value is true, the new request will be sent. Otherwise, the error that caused the retry attempt will be re-raised.
Defaults to idempotent?, from intarweb. This is because non-idempotent requests cannot be safely retried when it is unknown whether the previous request reached the server or not.[parameter] (max-redirect-depth [number])
The maximum number of allowed redirects, or #f if there is no limit. Currently there's no automatic redirect loop detection algorithm implemented.
Defaults to 5.[parameter] (client-software [software-spec])
This is the names, versions and comments of the software packages that the client is using, for use in the user-agent header which is automatically added to each request.
Defaults to (("Chicken Scheme HTTP-client" VERSION #f)), where VERSION is the version of this egg.
Connection management[procedure] (close-connection! uri)
Close the connection to the server associated with the URI.[procedure] (close-all-connections!)
Close all connections to all servers.
http-client's cookie management is supposed to be as automatic and DWIMmy as possible. This means it will write any cookie as instructed by a server and all stored cookies are automatically sent back to the server upon a new request.
However, in some cases you may want to take control of how cookies are stored.
The API described here should be considered unstable and it may change dramatically when someone comes up with a better way to handle cookies.[procedure] (get-cookies-for-uri uri)
Fetch a list of all cookies which ought to be sent to the given URI. Cookies are vectors of two elements: a name/value pair and an alist of attributes. In other words, these are the exact same values you can put in a cookie header.[procedure] (store-cookie! cookie)
Store the given cookie object in the cookiejar. This overwrites any cookie that is equal to this cookie, as defined by RFC 2965, section 3.3.3. Practically, this means that when the cookie's name, domain and path are equal to an existant one, it will be overwritten by the new one.[procedure] (delete-cookie! cookie)
Removes any cookie from the cookiejar that is equal to the given cookie (again, in the sense of RFC 2965, section 3.3.3).
- 0.1 Initial version
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