source: protocols/twitter/twitter_lib.c @ 4be0e34

/***************************************************************************\
*                                                                           *
*  BitlBee - An IRC to IM gateway                                           *
*  Simple module to facilitate twitter functionality.                       *
*                                                                           *
*  Copyright 2009 Geert Mulders <g.c.w.m.mulders@gmail.com>                 *
*                                                                           *
*  This library is free software; you can redistribute it and/or            *
*  modify it under the terms of the GNU Lesser General Public               *
*  License as published by the Free Software Foundation, version            *
*  2.1.                                                                     *
*                                                                           *
*  This library 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        *
*  Lesser General Public License for more details.                          *
*                                                                           *
*  You should have received a copy of the GNU Lesser General Public License *
*  along with this library; if not, write to the Free Software Foundation,  *
*  Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA           *
*                                                                           *
****************************************************************************/

/* For strptime(): */
#if(__sun)
#else
#define _XOPEN_SOURCE
#endif

#include "twitter_http.h"
#include "twitter.h"
#include "bitlbee.h"
#include "url.h"
#include "misc.h"
#include "base64.h"
#include "xmltree.h"
#include "twitter_lib.h"
#include <ctype.h>
#include <errno.h>

/* GLib < 2.12.0 doesn't have g_ascii_strtoll(), work around using system strtoll(). */
/* GLib < 2.12.4 can be buggy: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=488013 */
#if !GLIB_CHECK_VERSION(2,12,5)
#include <stdlib.h>
#include <limits.h>
#define g_ascii_strtoll strtoll
#endif

#define TXL_STATUS 1
#define TXL_USER 2
#define TXL_ID 3

struct twitter_xml_list {
        int type;
        gint64 next_cursor;
        GSList *list;
};

struct twitter_xml_user {
        char *name;
        char *screen_name;
};

struct twitter_xml_status {
        time_t created_at;
        char *text;
        struct twitter_xml_user *user;
        guint64 id, reply_to;
};

static void twitter_groupchat_init(struct im_connection *ic);

/**
 * Frees a twitter_xml_user struct.
 */
static void txu_free(struct twitter_xml_user *txu)
{
        if (txu == NULL)
                return;

        g_free(txu->name);
        g_free(txu->screen_name);
        g_free(txu);
}

/**
 * Frees a twitter_xml_status struct.
 */
static void txs_free(struct twitter_xml_status *txs)
{
        if (txs == NULL)
                return;

        g_free(txs->text);
        txu_free(txs->user);
        g_free(txs);
}

/**
 * Free a twitter_xml_list struct.
 * type is the type of list the struct holds.
 */
static void txl_free(struct twitter_xml_list *txl)
{
        GSList *l;
        if (txl == NULL)
                return;

        for (l = txl->list; l; l = g_slist_next(l)) {
                if (txl->type == TXL_STATUS) {
                        txs_free((struct twitter_xml_status *) l->data);
                } else if (txl->type == TXL_ID) {
                        g_free(l->data);
                } else if (txl->type == TXL_USER) {
                        txu_free(l->data);
                }
        }

        g_slist_free(txl->list);
        g_free(txl);
}

/**
 * Compare status elements
 */
static gint twitter_compare_elements(gconstpointer a, gconstpointer b)
{
        struct twitter_xml_status *a_status = (struct twitter_xml_status *) a;
        struct twitter_xml_status *b_status = (struct twitter_xml_status *) b;

        if (a_status->created_at < b_status->created_at) {
                return -1;
        } else if (a_status->created_at > b_status->created_at) {
                return 1;
        } else {
                return 0;
        }
}

/**
 * Add a buddy if it is not already added, set the status to logged in.
 */
static void twitter_add_buddy(struct im_connection *ic, char *name, const char *fullname)
{
        struct twitter_data *td = ic->proto_data;

        // Check if the buddy is already in the buddy list.
        if (!bee_user_by_handle(ic->bee, ic, name)) {
                char *mode = set_getstr(&ic->acc->set, "mode");

                // The buddy is not in the list, add the buddy and set the status to logged in.
                imcb_add_buddy(ic, name, NULL);
                imcb_rename_buddy(ic, name, fullname);
                if (g_strcasecmp(mode, "chat") == 0) {
                        /* Necessary so that nicks always get translated to the
                           exact Twitter username. */
                        imcb_buddy_nick_hint(ic, name, name);
                        imcb_chat_add_buddy(td->timeline_gc, name);
                } else if (g_strcasecmp(mode, "many") == 0)
                        imcb_buddy_status(ic, name, OPT_LOGGED_IN, NULL, NULL);
        }
}

/* Warning: May return a malloc()ed value, which will be free()d on the next
   call. Only for short-term use. NOT THREADSAFE!  */
char *twitter_parse_error(struct http_request *req)
{
        static char *ret = NULL;
        struct xt_parser *xp = NULL;
        struct xt_node *node, *err;

        g_free(ret);
        ret = NULL;

        if (req->body_size > 0) {
                xp = xt_new(NULL, NULL);
                xt_feed(xp, req->reply_body, req->body_size);
                
                for (node = xp->root; node; node = node->next)
                        if ((err = xt_find_node(node->children, "error")) && err->text_len > 0) {
                                ret = g_strdup_printf("%s (%s)", req->status_string, err->text);
                                break;
                        }

                xt_free(xp);
        }

        return ret ? ret : req->status_string;
}

static void twitter_http_get_friends_ids(struct http_request *req);

/**
 * Get the friends ids.
 */
void twitter_get_friends_ids(struct im_connection *ic, gint64 next_cursor)
{
        // Primitive, but hey! It works...      
        char *args[2];
        args[0] = "cursor";
        args[1] = g_strdup_printf("%lld", (long long) next_cursor);
        twitter_http(ic, TWITTER_FRIENDS_IDS_URL, twitter_http_get_friends_ids, ic, 0, args, 2);

        g_free(args[1]);
}

/**
 * Function to help fill a list.
 */
static xt_status twitter_xt_next_cursor(struct xt_node *node, struct twitter_xml_list *txl)
{
        char *end = NULL;

        if (node->text)
                txl->next_cursor = g_ascii_strtoll(node->text, &end, 10);
        if (end == NULL)
                txl->next_cursor = -1;

        return XT_HANDLED;
}

/**
 * Fill a list of ids.
 */
static xt_status twitter_xt_get_friends_id_list(struct xt_node *node, struct twitter_xml_list *txl)
{
        struct xt_node *child;

        // Set the list type.
        txl->type = TXL_ID;

        // The root <statuses> node should hold the list of statuses <status>
        // Walk over the nodes children.
        for (child = node->children; child; child = child->next) {
                if (g_strcasecmp("ids", child->name) == 0) {
                        struct xt_node *idc;
                        for (idc = child->children; idc; idc = idc->next)
                                if (g_strcasecmp(idc->name, "id") == 0)
                                        txl->list = g_slist_prepend(txl->list,
                                                g_memdup(idc->text, idc->text_len + 1));
                } else if (g_strcasecmp("next_cursor", child->name) == 0) {
                        twitter_xt_next_cursor(child, txl);
                }
        }

        return XT_HANDLED;
}

static void twitter_get_users_lookup(struct im_connection *ic);

/**
 * Callback for getting the friends ids.
 */
static void twitter_http_get_friends_ids(struct http_request *req)
{
        struct im_connection *ic;
        struct xt_parser *parser;
        struct twitter_xml_list *txl;
        struct twitter_data *td;

        ic = req->data;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic))
                return;

        td = ic->proto_data;

        // Check if the HTTP request went well. More strict checks as this is
        // the first request we do in a session.
        if (req->status_code == 401) {
                imcb_error(ic, "Authentication failure");
                imc_logout(ic, FALSE);
                return;
        } else if (req->status_code != 200) {
                // It didn't go well, output the error and return.
                imcb_error(ic, "Could not retrieve %s: %s",
                           TWITTER_FRIENDS_IDS_URL, twitter_parse_error(req));
                imc_logout(ic, TRUE);
                return;
        } else {
                td->http_fails = 0;
        }

        /* Create the room now that we "logged in". */
        if (!td->timeline_gc && g_strcasecmp(set_getstr(&ic->acc->set, "mode"), "chat") == 0)
                twitter_groupchat_init(ic);

        txl = g_new0(struct twitter_xml_list, 1);
        txl->list = td->follow_ids;

        // Parse the data.
        parser = xt_new(NULL, txl);
        xt_feed(parser, req->reply_body, req->body_size);
        twitter_xt_get_friends_id_list(parser->root, txl);
        xt_free(parser);

        td->follow_ids = txl->list;
        if (txl->next_cursor)
                /* These were just numbers. Up to 4000 in a response AFAIK so if we get here
                   we may be using a spammer account. \o/ */
                twitter_get_friends_ids(ic, txl->next_cursor);
        else
                /* Now to convert all those numbers into names.. */
                twitter_get_users_lookup(ic);

        txl->list = NULL;
        txl_free(txl);
}

static xt_status twitter_xt_get_users(struct xt_node *node, struct twitter_xml_list *txl);
static void twitter_http_get_users_lookup(struct http_request *req);

static void twitter_get_users_lookup(struct im_connection *ic)
{
        struct twitter_data *td = ic->proto_data;
        char *args[2] = {
                "user_id",
                NULL,
        };
        GString *ids = g_string_new("");
        int i;
        
        /* We can request up to 100 users at a time. */
        for (i = 0; i < 100 && td->follow_ids; i ++) {
                g_string_append_printf(ids, ",%s", (char*) td->follow_ids->data);
                g_free(td->follow_ids->data);
                td->follow_ids = g_slist_remove(td->follow_ids, td->follow_ids->data);
        }
        if (ids->len > 0) {
                args[1] = ids->str + 1;
                /* POST, because I think ids can be up to 1KB long. */
                twitter_http(ic, TWITTER_USERS_LOOKUP_URL, twitter_http_get_users_lookup, ic, 1, args, 2);
        } else {
                /* We have all users. Continue with login. (Get statuses.) */
                td->flags |= TWITTER_HAVE_FRIENDS;
                twitter_login_finish(ic);
        }
        g_string_free(ids, TRUE);
}

/**
 * Callback for getting (twitter)friends...
 *
 * Be afraid, be very afraid! This function will potentially add hundreds of "friends". "Who has 
 * hundreds of friends?" you wonder? You probably not, since you are reading the source of 
 * BitlBee... Get a life and meet new people!
 */
static void twitter_http_get_users_lookup(struct http_request *req)
{
        struct im_connection *ic = req->data;
        struct twitter_data *td;
        struct xt_parser *parser;
        struct twitter_xml_list *txl;
        GSList *l = NULL;
        struct twitter_xml_user *user;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic))
                return;

        td = ic->proto_data;

        if (req->status_code != 200) {
                // It didn't go well, output the error and return.
                imcb_error(ic, "Could not retrieve %s: %s",
                           TWITTER_USERS_LOOKUP_URL, twitter_parse_error(req));
                imc_logout(ic, TRUE);
                return;
        } else {
                td->http_fails = 0;
        }

        txl = g_new0(struct twitter_xml_list, 1);
        txl->list = NULL;

        // Parse the data.
        parser = xt_new(NULL, txl);
        xt_feed(parser, req->reply_body, req->body_size);

        // Get the user list from the parsed xml feed.
        twitter_xt_get_users(parser->root, txl);
        xt_free(parser);

        // Add the users as buddies.
        for (l = txl->list; l; l = g_slist_next(l)) {
                user = l->data;
                twitter_add_buddy(ic, user->screen_name, user->name);
        }

        // Free the structure.
        txl_free(txl);

        twitter_get_users_lookup(ic);
}

/**
 * Function to fill a twitter_xml_user struct.
 * It sets:
 *  - the name and
 *  - the screen_name.
 */
static xt_status twitter_xt_get_user(struct xt_node *node, struct twitter_xml_user *txu)
{
        struct xt_node *child;

        // Walk over the nodes children.
        for (child = node->children; child; child = child->next) {
                if (g_strcasecmp("name", child->name) == 0) {
                        txu->name = g_memdup(child->text, child->text_len + 1);
                } else if (g_strcasecmp("screen_name", child->name) == 0) {
                        txu->screen_name = g_memdup(child->text, child->text_len + 1);
                }
        }
        return XT_HANDLED;
}

/**
 * Function to fill a twitter_xml_list struct.
 * It sets:
 *  - all <user>s from the <users> element.
 */
static xt_status twitter_xt_get_users(struct xt_node *node, struct twitter_xml_list *txl)
{
        struct twitter_xml_user *txu;
        struct xt_node *child;

        // Set the type of the list.
        txl->type = TXL_USER;

        // The root <users> node should hold the list of users <user>
        // Walk over the nodes children.
        for (child = node->children; child; child = child->next) {
                if (g_strcasecmp("user", child->name) == 0) {
                        txu = g_new0(struct twitter_xml_user, 1);
                        twitter_xt_get_user(child, txu);
                        // Put the item in the front of the list.
                        txl->list = g_slist_prepend(txl->list, txu);
                }
        }

        return XT_HANDLED;
}

#ifdef __GLIBC__
#define TWITTER_TIME_FORMAT "%a %b %d %H:%M:%S %z %Y"
#else
#define TWITTER_TIME_FORMAT "%a %b %d %H:%M:%S +0000 %Y"
#endif

/**
 * Function to fill a twitter_xml_status struct.
 * It sets:
 *  - the status text and
 *  - the created_at timestamp and
 *  - the status id and
 *  - the user in a twitter_xml_user struct.
 */
static xt_status twitter_xt_get_status(struct xt_node *node, struct twitter_xml_status *txs)
{
        struct xt_node *child, *rt = NULL;

        // Walk over the nodes children.
        for (child = node->children; child; child = child->next) {
                if (g_strcasecmp("text", child->name) == 0) {
                        txs->text = g_memdup(child->text, child->text_len + 1);
                } else if (g_strcasecmp("retweeted_status", child->name) == 0) {
                        rt = child;
                } else if (g_strcasecmp("created_at", child->name) == 0) {
                        struct tm parsed;

                        /* Very sensitive to changes to the formatting of
                           this field. :-( Also assumes the timezone used
                           is UTC since C time handling functions suck. */
                        if (strptime(child->text, TWITTER_TIME_FORMAT, &parsed) != NULL)
                                txs->created_at = mktime_utc(&parsed);
                } else if (g_strcasecmp("user", child->name) == 0) {
                        txs->user = g_new0(struct twitter_xml_user, 1);
                        twitter_xt_get_user(child, txs->user);
                } else if (g_strcasecmp("id", child->name) == 0) {
                        txs->id = g_ascii_strtoull(child->text, NULL, 10);
                } else if (g_strcasecmp("in_reply_to_status_id", child->name) == 0) {
                        txs->reply_to = g_ascii_strtoull(child->text, NULL, 10);
                }
        }

        /* If it's a (truncated) retweet, get the original. Even if the API claims it
           wasn't truncated because it may be lying. */
        if (rt) {
                struct twitter_xml_status *rtxs = g_new0(struct twitter_xml_status, 1);
                if (twitter_xt_get_status(rt, rtxs) != XT_HANDLED) {
                        txs_free(rtxs);
                        return XT_HANDLED;
                }

                g_free(txs->text);
                txs->text = g_strdup_printf("RT @%s: %s", rtxs->user->screen_name, rtxs->text);
                txs_free(rtxs);
        } else {
                struct xt_node *urls, *url;
                
                urls = xt_find_path(node, "entities/urls");
                for (url = urls ? urls->children : NULL; url; url = url->next) {
                        /* "short" is a reserved word. :-P */
                        struct xt_node *kort = xt_find_node(url->children, "url");
                        struct xt_node *disp = xt_find_node(url->children, "display_url");
                        char *pos, *new;
                        
                        if (!kort || !kort->text || !disp || !disp->text ||
                            !(pos = strstr(txs->text, kort->text)))
                                continue;
                        
                        *pos = '\0';
                        new = g_strdup_printf("%s%s &lt;%s&gt;%s", txs->text, kort->text,
                                              disp->text, pos + strlen(kort->text));
                        
                        g_free(txs->text);
                        txs->text = new;
                }
        }

        return XT_HANDLED;
}

/**
 * Function to fill a twitter_xml_list struct.
 * It sets:
 *  - all <status>es within the <status> element and
 *  - the next_cursor.
 */
static xt_status twitter_xt_get_status_list(struct im_connection *ic, struct xt_node *node,
                                            struct twitter_xml_list *txl)
{
        struct twitter_xml_status *txs;
        struct xt_node *child;
        bee_user_t *bu;

        // Set the type of the list.
        txl->type = TXL_STATUS;

        // The root <statuses> node should hold the list of statuses <status>
        // Walk over the nodes children.
        for (child = node->children; child; child = child->next) {
                if (g_strcasecmp("status", child->name) == 0) {
                        txs = g_new0(struct twitter_xml_status, 1);
                        twitter_xt_get_status(child, txs);
                        // Put the item in the front of the list.
                        txl->list = g_slist_prepend(txl->list, txs);

                        if (txs->user && txs->user->screen_name &&
                            (bu = bee_user_by_handle(ic->bee, ic, txs->user->screen_name))) {
                                struct twitter_user_data *tud = bu->data;

                                if (txs->id > tud->last_id) {
                                        tud->last_id = txs->id;
                                        tud->last_time = txs->created_at;
                                }
                        }
                } else if (g_strcasecmp("next_cursor", child->name) == 0) {
                        twitter_xt_next_cursor(child, txl);
                }
        }

        return XT_HANDLED;
}

static char *twitter_msg_add_id(struct im_connection *ic,
                                struct twitter_xml_status *txs, const char *prefix)
{
        struct twitter_data *td = ic->proto_data;
        char *ret = NULL;

        if (!set_getbool(&ic->acc->set, "show_ids")) {
                if (*prefix)
                        return g_strconcat(prefix, txs->text, NULL);
                else
                        return NULL;
        }

        td->log[td->log_id].id = txs->id;
        td->log[td->log_id].bu = bee_user_by_handle(ic->bee, ic, txs->user->screen_name);
        if (txs->reply_to) {
                int i;
                for (i = 0; i < TWITTER_LOG_LENGTH; i++)
                        if (td->log[i].id == txs->reply_to) {
                                ret = g_strdup_printf("\002[\002%02d->%02d\002]\002 %s%s",
                                                      td->log_id, i, prefix, txs->text);
                                break;
                        }
        }
        if (ret == NULL)
                ret = g_strdup_printf("\002[\002%02d\002]\002 %s%s", td->log_id, prefix, txs->text);
        td->log_id = (td->log_id + 1) % TWITTER_LOG_LENGTH;

        return ret;
}

static void twitter_groupchat_init(struct im_connection *ic)
{
        char *name_hint;
        struct groupchat *gc;
        struct twitter_data *td = ic->proto_data;
        GSList *l;

        td->timeline_gc = gc = imcb_chat_new(ic, "twitter/timeline");

        name_hint = g_strdup_printf("%s_%s", td->prefix, ic->acc->user);
        imcb_chat_name_hint(gc, name_hint);
        g_free(name_hint);

        for (l = ic->bee->users; l; l = l->next) {
                bee_user_t *bu = l->data;
                if (bu->ic == ic)
                        imcb_chat_add_buddy(td->timeline_gc, bu->handle);
        }
}

/**
 * Function that is called to see the statuses in a groupchat window.
 */
static void twitter_groupchat(struct im_connection *ic, GSList * list)
{
        struct twitter_data *td = ic->proto_data;
        GSList *l = NULL;
        struct twitter_xml_status *status;
        struct groupchat *gc;
        guint64 last_id = 0;

        // Create a new groupchat if it does not exsist.
        if (!td->timeline_gc)
                twitter_groupchat_init(ic);

        gc = td->timeline_gc;
        if (!gc->joined)
                imcb_chat_add_buddy(gc, ic->acc->user);

        for (l = list; l; l = g_slist_next(l)) {
                char *msg;

                status = l->data;
                if (status->user == NULL || status->text == NULL || last_id == status->id)
                        continue;

                last_id = status->id;

                strip_html(status->text);

                msg = twitter_msg_add_id(ic, status, "");

                // Say it!
                if (g_strcasecmp(td->user, status->user->screen_name) == 0) {
                        imcb_chat_log(gc, "You: %s", msg ? msg : status->text);
                } else {
                        twitter_add_buddy(ic, status->user->screen_name, status->user->name);

                        imcb_chat_msg(gc, status->user->screen_name,
                                      msg ? msg : status->text, 0, status->created_at);
                }

                g_free(msg);

                // Update the timeline_id to hold the highest id, so that by the next request
                // we won't pick up the updates already in the list.
                td->timeline_id = MAX(td->timeline_id, status->id);
        }
}

/**
 * Function that is called to see statuses as private messages.
 */
static void twitter_private_message_chat(struct im_connection *ic, GSList * list)
{
        struct twitter_data *td = ic->proto_data;
        GSList *l = NULL;
        struct twitter_xml_status *status;
        char from[MAX_STRING];
        gboolean mode_one;
        guint64 last_id = 0;

        mode_one = g_strcasecmp(set_getstr(&ic->acc->set, "mode"), "one") == 0;

        if (mode_one) {
                g_snprintf(from, sizeof(from) - 1, "%s_%s", td->prefix, ic->acc->user);
                from[MAX_STRING - 1] = '\0';
        }

        for (l = list; l; l = g_slist_next(l)) {
                char *prefix = NULL, *text = NULL;

                status = l->data;
                if (status->user == NULL || status->text == NULL || last_id == status->id)
                        continue;

                last_id = status->id;

                strip_html(status->text);
                if (mode_one)
                        prefix = g_strdup_printf("\002<\002%s\002>\002 ",
                                                 status->user->screen_name);
                else
                        twitter_add_buddy(ic, status->user->screen_name, status->user->name);

                text = twitter_msg_add_id(ic, status, prefix ? prefix : "");

                imcb_buddy_msg(ic,
                               mode_one ? from : status->user->screen_name,
                               text ? text : status->text, 0, status->created_at);

                // Update the timeline_id to hold the highest id, so that by the next request
                // we won't pick up the updates already in the list.
                td->timeline_id = MAX(td->timeline_id, status->id);

                g_free(text);
                g_free(prefix);
        }
}

static void twitter_http_get_home_timeline(struct http_request *req);
static void twitter_http_get_mentions(struct http_request *req);

/**
 * Get the timeline with optionally mentions
 */
void twitter_get_timeline(struct im_connection *ic, gint64 next_cursor)
{
        struct twitter_data *td = ic->proto_data;
        gboolean include_mentions = set_getbool(&ic->acc->set, "fetch_mentions");

        if (td->flags & TWITTER_DOING_TIMELINE) {
                return;
        }

        td->flags |= TWITTER_DOING_TIMELINE;

        twitter_get_home_timeline(ic, next_cursor);

        if (include_mentions) {
                twitter_get_mentions(ic, next_cursor);
        }
}

/**
 * Call this one after receiving timeline/mentions. Show to user once we have
 * both.
 */
void twitter_flush_timeline(struct im_connection *ic)
{
        struct twitter_data *td = ic->proto_data;
        gboolean include_mentions = set_getbool(&ic->acc->set, "fetch_mentions");
        gboolean show_old_mentions = set_getbool(&ic->acc->set, "show_old_mentions");
        struct twitter_xml_list *home_timeline = td->home_timeline_obj;
        struct twitter_xml_list *mentions = td->mentions_obj;
        GSList *output = NULL;
        GSList *l;

        if (!(td->flags & TWITTER_GOT_TIMELINE)) {
                return;
        }

        if (include_mentions && !(td->flags & TWITTER_GOT_MENTIONS)) {
                return;
        }

        if (home_timeline && home_timeline->list) {
                for (l = home_timeline->list; l; l = g_slist_next(l)) {
                        output = g_slist_insert_sorted(output, l->data, twitter_compare_elements);
                }
        }

        if (include_mentions && mentions && mentions->list) {
                for (l = mentions->list; l; l = g_slist_next(l)) {
                        if (!show_old_mentions && output && twitter_compare_elements(l->data, output->data) < 0) {
                                continue;
                        }

                        output = g_slist_insert_sorted(output, l->data, twitter_compare_elements);
                }
        }

        // See if the user wants to see the messages in a groupchat window or as private messages.
        if (g_strcasecmp(set_getstr(&ic->acc->set, "mode"), "chat") == 0)
                twitter_groupchat(ic, output);
        else
                twitter_private_message_chat(ic, output);

        g_slist_free(output);

        if (home_timeline && home_timeline->list) {
                txl_free(home_timeline);
        }

        if (mentions && mentions->list) {
                txl_free(mentions);
        }

        td->flags &= ~(TWITTER_DOING_TIMELINE | TWITTER_GOT_TIMELINE | TWITTER_GOT_MENTIONS);
}

/**
 * Get the timeline.
 */
void twitter_get_home_timeline(struct im_connection *ic, gint64 next_cursor)
{
        struct twitter_data *td = ic->proto_data;

        td->home_timeline_obj = NULL;
        td->flags &= ~TWITTER_GOT_TIMELINE;

        char *args[6];
        args[0] = "cursor";
        args[1] = g_strdup_printf("%lld", (long long) next_cursor);
        args[2] = "include_entities";
        args[3] = "true";
        if (td->timeline_id) {
                args[4] = "since_id";
                args[5] = g_strdup_printf("%llu", (long long unsigned int) td->timeline_id);
        }

        if (twitter_http(ic, TWITTER_HOME_TIMELINE_URL, twitter_http_get_home_timeline, ic, 0, args,
                     td->timeline_id ? 6 : 4) == NULL) {
                if (++td->http_fails >= 5)
                        imcb_error(ic, "Could not retrieve %s: %s",
                                   TWITTER_HOME_TIMELINE_URL, "connection failed");
                td->flags |= TWITTER_GOT_TIMELINE;
                twitter_flush_timeline(ic);
        }

        g_free(args[1]);
        if (td->timeline_id) {
                g_free(args[5]);
        }
}

/**
 * Get mentions.
 */
void twitter_get_mentions(struct im_connection *ic, gint64 next_cursor)
{
        struct twitter_data *td = ic->proto_data;

        td->mentions_obj = NULL;
        td->flags &= ~TWITTER_GOT_MENTIONS;

        char *args[6];
        args[0] = "cursor";
        args[1] = g_strdup_printf("%lld", (long long) next_cursor);
        args[2] = "include_entities";
        args[3] = "true";
        if (td->timeline_id) {
                args[4] = "since_id";
                args[5] = g_strdup_printf("%llu", (long long unsigned int) td->timeline_id);
        }

        if (twitter_http(ic, TWITTER_MENTIONS_URL, twitter_http_get_mentions, ic, 0, args,
                     td->timeline_id ? 6 : 4) == NULL) {
                if (++td->http_fails >= 5)
                        imcb_error(ic, "Could not retrieve %s: %s",
                                   TWITTER_MENTIONS_URL, "connection failed");
                td->flags |= TWITTER_GOT_MENTIONS;
                twitter_flush_timeline(ic);
        }

        g_free(args[1]);
        if (td->timeline_id) {
                g_free(args[5]);
        }
}

/**
 * Callback for getting the home timeline.
 */
static void twitter_http_get_home_timeline(struct http_request *req)
{
        struct im_connection *ic = req->data;
        struct twitter_data *td;
        struct xt_parser *parser;
        struct twitter_xml_list *txl;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic))
                return;

        td = ic->proto_data;

        // Check if the HTTP request went well.
        if (req->status_code == 200) {
                td->http_fails = 0;
                if (!(ic->flags & OPT_LOGGED_IN))
                        imcb_connected(ic);
        } else if (req->status_code == 401) {
                imcb_error(ic, "Authentication failure");
                imc_logout(ic, FALSE);
                goto end;
        } else {
                // It didn't go well, output the error and return.
                if (++td->http_fails >= 5)
                        imcb_error(ic, "Could not retrieve %s: %s",
                                   TWITTER_HOME_TIMELINE_URL, twitter_parse_error(req));

                goto end;
        }

        txl = g_new0(struct twitter_xml_list, 1);
        txl->list = NULL;

        // Parse the data.
        parser = xt_new(NULL, txl);
        xt_feed(parser, req->reply_body, req->body_size);
        // The root <statuses> node should hold the list of statuses <status>
        twitter_xt_get_status_list(ic, parser->root, txl);
        xt_free(parser);

        td->home_timeline_obj = txl;

      end:
        td->flags |= TWITTER_GOT_TIMELINE;

        twitter_flush_timeline(ic);
}

/**
 * Callback for getting mentions.
 */
static void twitter_http_get_mentions(struct http_request *req)
{
        struct im_connection *ic = req->data;
        struct twitter_data *td;
        struct xt_parser *parser;
        struct twitter_xml_list *txl;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic))
                return;

        td = ic->proto_data;

        // Check if the HTTP request went well.
        if (req->status_code == 200) {
                td->http_fails = 0;
                if (!(ic->flags & OPT_LOGGED_IN))
                        imcb_connected(ic);
        } else if (req->status_code == 401) {
                imcb_error(ic, "Authentication failure");
                imc_logout(ic, FALSE);
                goto end;
        } else {
                // It didn't go well, output the error and return.
                if (++td->http_fails >= 5)
                        imcb_error(ic, "Could not retrieve %s: %s",
                                   TWITTER_MENTIONS_URL, twitter_parse_error(req));

                goto end;
        }

        txl = g_new0(struct twitter_xml_list, 1);
        txl->list = NULL;

        // Parse the data.
        parser = xt_new(NULL, txl);
        xt_feed(parser, req->reply_body, req->body_size);
        // The root <statuses> node should hold the list of statuses <status>
        twitter_xt_get_status_list(ic, parser->root, txl);
        xt_free(parser);

        td->mentions_obj = txl;

      end:
        td->flags |= TWITTER_GOT_MENTIONS;

        twitter_flush_timeline(ic);
}

/**
 * Callback to use after sending a POST request to twitter.
 * (Generic, used for a few kinds of queries.)
 */
static void twitter_http_post(struct http_request *req)
{
        struct im_connection *ic = req->data;
        struct twitter_data *td;

        // Check if the connection is still active.
        if (!g_slist_find(twitter_connections, ic))
                return;

        td = ic->proto_data;
        td->last_status_id = 0;

        // Check if the HTTP request went well.
        if (req->status_code != 200) {
                // It didn't go well, output the error and return.
                imcb_error(ic, "HTTP error: %s", twitter_parse_error(req));
                return;
        }

        if (req->body_size > 0) {
                struct xt_parser *xp = NULL;
                struct xt_node *node;

                xp = xt_new(NULL, NULL);
                xt_feed(xp, req->reply_body, req->body_size);

                if ((node = xt_find_node(xp->root, "status")) &&
                    (node = xt_find_node(node->children, "id")) && node->text)
                        td->last_status_id = g_ascii_strtoull(node->text, NULL, 10);

                xt_free(xp);
        }
}

/**
 * Function to POST a new status to twitter.
 */
void twitter_post_status(struct im_connection *ic, char *msg, guint64 in_reply_to)
{
        char *args[4] = {
                "status", msg,
                "in_reply_to_status_id",
                g_strdup_printf("%llu", (unsigned long long) in_reply_to)
        };
        twitter_http(ic, TWITTER_STATUS_UPDATE_URL, twitter_http_post, ic, 1,
                     args, in_reply_to ? 4 : 2);
        g_free(args[3]);
}


/**
 * Function to POST a new message to twitter.
 */
void twitter_direct_messages_new(struct im_connection *ic, char *who, char *msg)
{
        char *args[4];
        args[0] = "screen_name";
        args[1] = who;
        args[2] = "text";
        args[3] = msg;
        // Use the same callback as for twitter_post_status, since it does basically the same.
        twitter_http(ic, TWITTER_DIRECT_MESSAGES_NEW_URL, twitter_http_post, ic, 1, args, 4);
}

void twitter_friendships_create_destroy(struct im_connection *ic, char *who, int create)
{
        char *args[2];
        args[0] = "screen_name";
        args[1] = who;
        twitter_http(ic, create ? TWITTER_FRIENDSHIPS_CREATE_URL : TWITTER_FRIENDSHIPS_DESTROY_URL,
                     twitter_http_post, ic, 1, args, 2);
}

void twitter_status_destroy(struct im_connection *ic, guint64 id)
{
        char *url;
        url = g_strdup_printf("%s%llu%s", TWITTER_STATUS_DESTROY_URL,
                              (unsigned long long) id, ".xml");
        twitter_http(ic, url, twitter_http_post, ic, 1, NULL, 0);
        g_free(url);
}

void twitter_status_retweet(struct im_connection *ic, guint64 id)
{
        char *url;
        url = g_strdup_printf("%s%llu%s", TWITTER_STATUS_RETWEET_URL,
                              (unsigned long long) id, ".xml");
        twitter_http(ic, url, twitter_http_post, ic, 1, NULL, 0);
        g_free(url);
}