/* This file is part of GNUnet Copyright (C) 2014, 2015, 2016 GNUnet e.V. GNUnet is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. GNUnet is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details. */ /** * @file src/include/gnunet_curl_lib.h * @brief library to make it easy to download JSON replies over HTTP * @author Sree Harsha Totakura * @author Christian Grothoff * * @defgroup curl CURL integration library * Download JSON using libcurl. * @{ */ #ifndef GNUNET_CURL_LIB_H #define GNUNET_CURL_LIB_H #if HAVE_CURL_CURL_H #include #elif HAVE_GNURL_CURL_H #include #else #error "needs curl or gnurl" #endif #include #include "gnunet_util_lib.h" /** * Function called by the context to ask for the event loop to be * rescheduled, that is the application should call * #GNUNET_CURL_get_select_info() as the set of sockets we care about * just changed. * * @param cls closure */ typedef void (*GNUNET_CURL_RescheduleCallback)(void *cls); /** * Initialise this library. This function should be called before using any of * the following functions. * * @param cb function to call when rescheduling is required * @param cb_cls closure for @a cb * @return library context */ struct GNUNET_CURL_Context * GNUNET_CURL_init (GNUNET_CURL_RescheduleCallback cb, void *cb_cls); /** * Obtain the information for a select() call to wait until * #GNUNET_CURL_perform() is ready again. * * Basically, a client should use this API to prepare for select(), * then block on select(), then call #GNUNET_CURL_perform() and then * start again until the work with the context is done. * * This function will NOT zero out the sets and assumes that @a max_fd * and @a timeout are already set to minimal applicable values. It is * safe to give this API FD-sets and @a max_fd and @a timeout that are * already initialized to some other descriptors that need to go into * the select() call. * * @param ctx context to get the event loop information for * @param read_fd_set will be set for any pending read operations * @param write_fd_set will be set for any pending write operations * @param except_fd_set is here because curl_multi_fdset() has this argument * @param max_fd set to the highest FD included in any set; * if the existing sets have no FDs in it, the initial * value should be "-1". (Note that `max_fd + 1` will need * to be passed to select().) * @param timeout set to the timeout in milliseconds (!); -1 means * no timeout (NULL, blocking forever is OK), 0 means to * proceed immediately with #GNUNET_CURL_perform(). */ void GNUNET_CURL_get_select_info (struct GNUNET_CURL_Context *ctx, fd_set *read_fd_set, fd_set *write_fd_set, fd_set *except_fd_set, int *max_fd, long *timeout); /** * Run the main event loop for the CURL interaction. * * @param ctx the library context */ void GNUNET_CURL_perform (struct GNUNET_CURL_Context *ctx); /** * Cleanup library initialisation resources. This function should be called * after using this library to cleanup the resources occupied during library's * initialisation. * * @param ctx the library context */ void GNUNET_CURL_fini (struct GNUNET_CURL_Context *ctx); /** * Entry in the context's job queue. */ struct GNUNET_CURL_Job; /** * Function to call upon completion of a job. * * @param cls closure * @param response_code HTTP response code from server, 0 on hard error * @param json response, NULL if response was not in JSON format */ typedef void (*GNUNET_CURL_JobCompletionCallback)(void *cls, long response_code, const json_t *json); /** * Schedule a CURL request to be executed and call the given @a jcc * upon its completion. Note that the context will make use of the * CURLOPT_PRIVATE facility of the CURL @a eh. * * This function modifies the CURL handle to add the * "Content-Type: application/json" header if @a add_json is set. * * @param ctx context to execute the job in * @param eh curl easy handle for the request, will * be executed AND cleaned up * @param add_json add "application/json" content type header * @param jcc callback to invoke upon completion * @param jcc_cls closure for @a jcc * @return NULL on error (in this case, @eh is still released!) */ struct GNUNET_CURL_Job * GNUNET_CURL_job_add (struct GNUNET_CURL_Context *ctx, CURL *eh, int add_json, GNUNET_CURL_JobCompletionCallback jcc, void *jcc_cls); /** * Cancel a job. Must only be called before the job completion * callback is called for the respective job. * * @param job job to cancel */ void GNUNET_CURL_job_cancel (struct GNUNET_CURL_Job *job); /* ******* GNUnet SCHEDULER integration ************ */ /** * Closure for #GNUNET_CURL_gnunet_scheduler_reschedule(). */ struct GNUNET_CURL_RescheduleContext; /** * Initialize reschedule context. * * @param ctx context to manage * @return closure for #GNUNET_CURL_gnunet_scheduler_reschedule(). */ struct GNUNET_CURL_RescheduleContext * GNUNET_CURL_gnunet_rc_create (struct GNUNET_CURL_Context *ctx); /** * Destroy reschedule context. * * @param rc context to destroy */ void GNUNET_CURL_gnunet_rc_destroy (struct GNUNET_CURL_RescheduleContext *rc); /** * Implementation of the #GNUNET_CURL_RescheduleCallback for GNUnet's * scheduler. Will run the CURL context using GNUnet's scheduler. * Note that you MUST immediately destroy the reschedule context after * calling #GNUNET_CURL_fini(). * * @param cls must point to a `struct GNUNET_CURL_RescheduleContext *` * (pointer to a pointer!) */ void GNUNET_CURL_gnunet_scheduler_reschedule (void *cls); #endif /** @} */ /* end of group */ /* end of gnunet_curl_lib.h */