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netsurf/content/fetchcache.c

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/*
* Copyright 2005 James Bursa <bursa@users.sourceforge.net>
*
* This file is part of NetSurf, http://www.netsurf-browser.org/
*
* NetSurf is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* NetSurf 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/** \file
* High-level fetching, caching and conversion (implementation).
*
* The implementation checks the cache for the requested URL. If it is not
* present, a content is created and a fetch is initiated. As the status of the
* fetch changes and data is received, the content is updated appropriately.
*/
#define _GNU_SOURCE /* for strndup */
#include <assert.h>
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <regex.h>
#include <time.h>
#include <unistd.h>
#include <curl/curl.h> /* for curl_getdate() */
#include "utils/config.h"
#include "content/content.h"
#include "content/fetchcache.h"
#include "content/fetch.h"
#include "utils/log.h"
#include "utils/messages.h"
#include "utils/talloc.h"
#include "utils/url.h"
#include "utils/utils.h"
static char error_page[1000];
static regex_t re_content_type;
static void fetchcache_callback(fetch_msg msg, void *p, const void *data,
unsigned long size);
static char *fetchcache_parse_type(const char *s, char **params[]);
static void fetchcache_parse_header(struct content *c, const char *data,
size_t size);
static void fetchcache_error_page(struct content *c, const char *error);
static void fetchcache_cache_update(struct content *c);
static void fetchcache_cache_clone(struct content *c,
const struct cache_data *data);
static void fetchcache_notmodified(struct content *c, const void *data);
static void fetchcache_redirect(struct content *c, const void *data,
unsigned long size);
/**
* Retrieve a URL or prepare to fetch, convert, and cache it.
*
* The caller must supply a callback function which is called when anything
* interesting happens to the content which is returned. See content.h.
*
* \param url address to fetch
* \param callback function to call when anything interesting happens to
* the new content
* \param p1 user parameter for callback (may be a pointer or integer)
* \param p2 user parameter for callback (may be a pointer or integer)
* \param width available space
* \param height available space
* \param no_error_pages if an error occurs, send CONTENT_MSG_ERROR instead
* of generating an error page
* \param post_urlenc url encoded post data, or 0 if none
* \param post_multipart multipart post data, or 0 if none
* \param verifiable this transaction is verifiable
* \param download download, rather than render content
* \return a new content, or 0 on memory exhaustion
*
* On success, call fetchcache_go() to start work on the new content.
*/
struct content * fetchcache(const char *url,
void (*callback)(content_msg msg, struct content *c,
intptr_t p1, intptr_t p2, union content_msg_data data),
intptr_t p1, intptr_t p2,
int width, int height,
bool no_error_pages,
char *post_urlenc,
struct form_successful_control *post_multipart,
bool verifiable,
bool download)
{
struct content *c;
char *url1;
char *hash, *query;
char *etag = 0;
time_t date = 0;
if (strncasecmp(url, "file:///", 8) &&
strncasecmp(url, "file:/", 6) == 0) {
/* Manipulate file URLs into correct format */
if (strncasecmp(url, "file://", 7) == 0) {
/* file://path */
url1 = malloc(7 + strlen(url));
if (!url1)
return NULL;
strcpy(url1, "file://");
strcat(url1 + 7, url + 6);
} else {
/* file:/... */
url1 = malloc(7 + strlen(url));
if (!url1)
return NULL;
strcpy(url1, "file://");
strcat(url1 + 7, url + 5);
}
} else {
/* simply duplicate the URL */
if ((url1 = strdup(url)) == NULL)
return NULL;
}
/* strip fragment identifier */
if ((hash = strchr(url1, '#')) != NULL)
*hash = 0;
/* look for query; we don't cache URLs with a query segment */
query = strchr(url1, '?');
LOG(("url %s", url1));
if (!post_urlenc && !post_multipart && !download && !query) {
if ((c = content_get(url1)) != NULL) {
struct cache_data *cd = &c->cache_data;
int current_age, freshness_lifetime;
/* Calculate staleness of cached content as per
* RFC 2616 13.2.3/13.2.4 */
current_age = max(0, (cd->res_time - cd->date));
current_age = max(current_age,
(cd->age == INVALID_AGE) ? 0
: cd->age);
current_age += cd->res_time - cd->req_time +
time(0) - cd->res_time;
freshness_lifetime =
(cd->max_age != INVALID_AGE) ? cd->max_age :
(cd->expires != 0) ? cd->expires - cd->date :
(cd->last_modified != 0) ?
(time(0) - cd->last_modified) / 10 :
0;
if (freshness_lifetime > current_age ||
cd->date == 0) {
/* Ok, either a fresh content or we're
* currently fetching the selected content
* (therefore it must be fresh) */
free(url1);
if (!content_add_user(c, callback, p1, p2))
return NULL;
else
return c;
}
/* Ok. We have a cache entry, but it appears stale.
* Therefore, validate it. */
if (cd->last_modified)
date = cd->last_modified;
else
date = c->cache_data.date;
etag = c->cache_data.etag;
}
}
c = content_create(url1);
free(url1);
if (!c)
return NULL;
/* Fill in cache validation fields (if present) */
if (date)
c->cache_data.date = date;
if (etag) {
c->cache_data.etag = talloc_strdup(c, etag);
if (!c->cache_data.etag)
return NULL;
}
if (!content_add_user(c, callback, p1, p2)) {
return NULL;
}
if (!post_urlenc && !post_multipart && !download && !query)
c->fresh = true;
c->width = width;
c->height = height;
c->no_error_pages = no_error_pages;
c->download = download;
return c;
}
/**
* Start fetching and converting a content.
*
* \param content content to fetch, as returned by fetchcache()
* \param referer referring URL, or 0
* \param callback function to call when anything interesting happens to
* the new content
* \param p1 user parameter for callback
* \param p2 user parameter for callback
* \param width available space
* \param height available space
* \param post_urlenc url encoded post data, or 0 if none
* \param post_multipart multipart post data, or 0 if none
* \param verifiable this transaction is verifiable
* \param parent_url URL of fetch which spawned this one, or 0 if none
*
* Errors will be sent back through the callback.
*/
void fetchcache_go(struct content *content, const char *referer,
void (*callback)(content_msg msg, struct content *c,
intptr_t p1, intptr_t p2, union content_msg_data data),
intptr_t p1, intptr_t p2,
int width, int height,
char *post_urlenc,
struct form_successful_control *post_multipart,
bool verifiable, const char *parent_url)
{
char error_message[500];
union content_msg_data msg_data;
LOG(("url %s, status %s", content->url,
content_status_name[content->status]));
/* We may well have been asked to fetch an URL using a protocol
* that we can't support. Check for this here and, if we can't
* perform the fetch, notify the caller and exit */
if (!fetch_can_fetch(content->url)) {
/* The only case where this should fail is if we're a
* brand new content with no active fetch. If we're not,
* another content with the same URL somehow got through
* the fetch_can_fetch check. That should be impossible.
*/
assert(content->status == CONTENT_STATUS_TYPE_UNKNOWN &&
!content->fetch);
snprintf(error_message, sizeof error_message,
messages_get("InvalidURL"),
content->url);
if (content->no_error_pages) {
/* Mark as in error so content is destroyed
* on cache clean */
content->status = CONTENT_STATUS_ERROR;
msg_data.error = error_message;
callback(CONTENT_MSG_ERROR,
content, p1, p2, msg_data);
} else {
fetchcache_error_page(content, error_message);
}
return;
}
if (content->status == CONTENT_STATUS_TYPE_UNKNOWN &&
content->fetch) {
/* fetching, but not yet received any response:
* no action required */
} else if (content->status == CONTENT_STATUS_TYPE_UNKNOWN) {
/* brand new content: start fetch */
char **headers;
int i = 0;
char *etag = content->cache_data.etag;
time_t date = content->cache_data.date;
content->cache_data.req_time = time(NULL);
content->cache_data.res_time = 0;
content->cache_data.date = 0;
content->cache_data.expires = 0;
content->cache_data.age = INVALID_AGE;
content->cache_data.max_age = INVALID_AGE;
content->cache_data.no_cache = false;
content->cache_data.etag = 0;
content->cache_data.last_modified = 0;
headers = malloc(3 * sizeof(char *));
if (!headers) {
content->status = CONTENT_STATUS_ERROR;
msg_data.error = messages_get("NoMemory");
callback(CONTENT_MSG_ERROR, content, p1, p2,
msg_data);
return;
}
if (etag) {
headers[i] = malloc(15 + strlen(etag) + 1);
if (!headers[i]) {
free(headers);
content->status = CONTENT_STATUS_ERROR;
msg_data.error = messages_get("NoMemory");
callback(CONTENT_MSG_ERROR, content, p1, p2,
msg_data);
return;
}
sprintf(headers[i++], "If-None-Match: %s", etag);
talloc_free(etag);
}
if (date) {
headers[i] = malloc(19 + 29 + 1);
if (!headers[i]) {
while (--i >= 0) {
free(headers[i]);
}
free(headers);
content->status = CONTENT_STATUS_ERROR;
msg_data.error = messages_get("NoMemory");
callback(CONTENT_MSG_ERROR, content, p1, p2,
msg_data);
return;
}
sprintf(headers[i++], "If-Modified-Since: %s",
rfc1123_date(date));
}
headers[i] = 0;
content->fetch = fetch_start(content->url, referer,
fetchcache_callback, content,
content->no_error_pages,
post_urlenc, post_multipart, verifiable,
parent_url, headers);
for (i = 0; headers[i]; i++)
free(headers[i]);
free(headers);
if (!content->fetch) {
LOG(("warning: fetch_start failed"));
snprintf(error_message, sizeof error_message,
messages_get("InvalidURL"),
content->url);
if (content->no_error_pages) {
content->status = CONTENT_STATUS_ERROR;
msg_data.error = error_message;
content_broadcast(content, CONTENT_MSG_ERROR,
msg_data);
} else {
fetchcache_error_page(content, error_message);
}
}
/* in these remaining cases, we have to 'catch up' with the content's
* status, ie. send the same messages as if the content was
* gradually getting to the current status from TYPE_UNKNOWN */
} else if (content->status == CONTENT_STATUS_LOADING) {
callback(CONTENT_MSG_LOADING, content, p1, p2, msg_data);
} else if (content->status == CONTENT_STATUS_READY) {
callback(CONTENT_MSG_LOADING, content, p1, p2, msg_data);
if (content_find_user(content, callback, p1, p2))
callback(CONTENT_MSG_READY, content, p1, p2, msg_data);
} else if (content->status == CONTENT_STATUS_DONE) {
callback(CONTENT_MSG_LOADING, content, p1, p2, msg_data);
if (content->available_width != width)
content_reformat(content, width, height);
if (content_find_user(content, callback, p1, p2))
callback(CONTENT_MSG_READY, content, p1, p2, msg_data);
if (content_find_user(content, callback, p1, p2))
callback(CONTENT_MSG_DONE, content, p1, p2, msg_data);
} else if (content->status == CONTENT_STATUS_ERROR) {
/* shouldn't usually occur */
msg_data.error = messages_get("MiscError");
callback(CONTENT_MSG_ERROR, content, p1, p2, msg_data);
}
}
/**
* Callback function for fetch.
*
* This is called when the status of a fetch changes.
*/
void fetchcache_callback(fetch_msg msg, void *p, const void *data,
unsigned long size)
{
bool res;
struct content *c = p;
content_type type;
char *mime_type;
char **params;
unsigned int i;
union content_msg_data msg_data;
switch (msg) {
case FETCH_TYPE:
c->total_size = size;
c->http_code = fetch_http_code(c->fetch);
mime_type = fetchcache_parse_type(data, &params);
if (!mime_type) {
msg_data.error = messages_get("NoMemory");
content_broadcast(c, CONTENT_MSG_ERROR,
msg_data);
fetch_abort(c->fetch);
c->fetch = 0;
return;
}
type = content_lookup(mime_type);
res = content_set_type(c,
c->download ? CONTENT_OTHER : type,
mime_type, (const char **) params);
free(mime_type);
for (i = 0; params[i]; i++)
free(params[i]);
free(params);
if (!res) {
fetch_abort(c->fetch);
c->fetch = 0;
}
if (c->cache_data.date || c->cache_data.etag) {
/* We've just made a conditional request
* that returned with something other
* than 304. Therefore, there's a stale
* content floating around in the cache.
* Hunt it down and mark it as stale, so
* it'll get cleaned when unused. We
* assume it's either READY or DONE --
* anything else is of marginal staleness
* (or in error, which will cause it to
* be flushed from the cache, anyway)
*/
struct content *stale_content =
content_get_ready(c->url);
if (stale_content)
stale_content->fresh = false;
}
break;
case FETCH_PROGRESS:
if (size)
content_set_status(c,
messages_get("RecPercent"),
data, (unsigned int)size);
else
content_set_status(c,
messages_get("Received"),
data);
content_broadcast(c, CONTENT_MSG_STATUS, msg_data);
break;
case FETCH_HEADER:
fetchcache_parse_header(c, data, size);
break;
case FETCH_DATA:
if (!content_process_data(c, data, size)) {
fetch_abort(c->fetch);
c->fetch = 0;
}
break;
case FETCH_FINISHED:
fetchcache_cache_update(c);
c->fetch = 0;
content_set_status(c, messages_get("Converting"),
c->source_size);
content_broadcast(c, CONTENT_MSG_STATUS, msg_data);
content_convert(c, c->width, c->height);
break;
case FETCH_ERROR:
LOG(("FETCH_ERROR, '%s'", (const char *)data));
c->fetch = 0;
if (c->no_error_pages) {
c->status = CONTENT_STATUS_ERROR;
msg_data.error = data;
content_broadcast(c, CONTENT_MSG_ERROR,
msg_data);
} else {
content_reset(c);
fetchcache_error_page(c, data);
}
break;
case FETCH_REDIRECT:
fetchcache_redirect(c, data, size);
break;
case FETCH_NOTMODIFIED:
fetchcache_notmodified(c, data);
break;
#ifdef WITH_AUTH
case FETCH_AUTH:
/* data -> string containing the Realm */
LOG(("FETCH_AUTH, '%s'", (const char *)data));
c->fetch = 0;
msg_data.auth_realm = data;
content_broadcast(c, CONTENT_MSG_AUTH, msg_data);
/* set the status to ERROR so that the content is
* destroyed in content_clean() */
c->status = CONTENT_STATUS_ERROR;
break;
#endif
#ifdef WITH_SSL
case FETCH_CERT_ERR:
c->fetch = 0;
/* set the status to ERROR so that the content is
* destroyed in content_clean() */
c->status = CONTENT_STATUS_ERROR;
msg_data.ssl.certs = data;
msg_data.ssl.num = size;
content_broadcast(c, CONTENT_MSG_SSL, msg_data);
break;
#endif
default:
assert(0);
}
}
/**
* Initialise the fetchcache module.
*/
void fetchcache_init(void)
{
regcomp_wrapper(&re_content_type,
"^([-0-9a-zA-Z_.]+/[-0-9a-zA-Z_.+]+)[ \t]*"
"(;[ \t]*([-0-9a-zA-Z_.]+)="
"([-0-9a-zA-Z_.]+|\"([^\"]|[\\].)*\")[ \t]*)*$",
REG_EXTENDED);
}
/**
* Parse a Content-Type header.
*
* \param s a Content-Type header
* \param params updated to point to an array of strings, ordered attribute,
* value, attribute, ..., 0
* \return a new string containing the MIME-type, or 0 on memory exhaustion
*/
#define MAX_ATTRS 10
char *fetchcache_parse_type(const char *s, char **params[])
{
char *type = 0;
unsigned int i;
int r;
regmatch_t pmatch[2 + MAX_ATTRS * 3];
*params = malloc((MAX_ATTRS * 2 + 2) * sizeof (*params)[0]);
if (!*params)
goto no_memory;
for (i = 0; i != MAX_ATTRS * 2 + 2; i++)
(*params)[i] = 0;
r = regexec(&re_content_type, s, 2 + MAX_ATTRS * 3, pmatch, 0);
if (r) {
char *semi;
LOG(("failed to parse content-type '%s'", s));
/* The mime type must be first, so only copy up to the
* first semicolon in the string. This allows us to have
* a better attempt at handling pages sent with broken
* Content-Type headers. Obviously, any truly broken
* Content-Type headers will be unaffected by this heuristic
*/
semi = strchr(s, ';');
if (semi)
type = strndup(s, semi - s);
else
type = strdup(s);
if (!type)
goto no_memory;
return type;
}
type = strndup(s + pmatch[1].rm_so, pmatch[1].rm_eo - pmatch[1].rm_so);
if (!type) {
free(*params);
return 0;
}
/* parameters */
for (i = 0; i != MAX_ATTRS && pmatch[2 + 3 * i].rm_so != -1; i++) {
(*params)[2 * i] = strndup(s + pmatch[2 + 3 * i + 1].rm_so,
pmatch[2 + 3 * i + 1].rm_eo -
pmatch[2 + 3 * i + 1].rm_so);
(*params)[2 * i + 1] = strndup(s + pmatch[2 + 3 * i + 2].rm_so,
pmatch[2 + 3 * i + 2].rm_eo -
pmatch[2 + 3 * i + 2].rm_so);
if (!(*params)[2 * i] || !(*params)[2 * i + 1])
goto no_memory;
}
(*params)[2 * i] = 0;
return type;
no_memory:
for (i = 0; i != MAX_ATTRS * 2 + 2; i++)
free((*params)[i]);
free(*params);
free(type);
return 0;
}
/**
* Parse an HTTP response header.
*
* See RFC 2616 4.2.
*/
void fetchcache_parse_header(struct content *c, const char *data,
size_t size)
{
size_t i;
#define SKIP_ST(o) for (i = (o); i < size && (data[i] == ' ' || data[i] == '\t'); i++)
/* Set fetch response time if not already set */
if (c->cache_data.res_time == 0)
c->cache_data.res_time = time(NULL);
if (5 < size && strncasecmp(data, "Date:", 5) == 0) {
/* extract Date header */
SKIP_ST(5);
if (i < size)
c->cache_data.date = curl_getdate(&data[i], NULL);
} else if (4 < size && strncasecmp(data, "Age:", 4) == 0) {
/* extract Age header */
SKIP_ST(4);
if (i < size && '0' <= data[i] && data[i] <= '9')
c->cache_data.age = atoi(data + i);
} else if (8 < size && strncasecmp(data, "Expires:", 8) == 0) {
/* extract Expires header */
SKIP_ST(8);
if (i < size)
c->cache_data.expires = curl_getdate(&data[i], NULL);
} else if (14 < size && strncasecmp(data, "Cache-Control:", 14) == 0) {
/* extract and parse Cache-Control header */
size_t comma;
SKIP_ST(14);
while (i < size) {
for (comma = i; comma < size; comma++)
if (data[comma] == ',')
break;
SKIP_ST(i);
if (8 < comma - i && (strncasecmp(data + i, "no-cache", 8) == 0 || strncasecmp(data + i, "no-store", 8) == 0))
/* When we get a disk cache we should
* distinguish between these two */
c->cache_data.no_cache = true;
else if (7 < comma - i && strncasecmp(data + i, "max-age", 7) == 0) {
for (; i < comma; i++)
if (data[i] == '=')
break;
SKIP_ST(i+1);
if (i < comma)
c->cache_data.max_age =
atoi(data + i);
}
i = comma + 1;
}
} else if (5 < size && strncasecmp(data, "ETag:", 5) == 0) {
/* extract ETag header */
talloc_free(c->cache_data.etag);
c->cache_data.etag = talloc_array(c, char, size);
if (!c->cache_data.etag) {
LOG(("malloc failed"));
return;
}
SKIP_ST(5);
strncpy(c->cache_data.etag, data + i, size - i);
c->cache_data.etag[size - i] = '\0';
for (i = size - i - 1; ((int) i) >= 0 &&
(c->cache_data.etag[i] == ' ' ||
c->cache_data.etag[i] == '\t' ||
c->cache_data.etag[i] == '\r' ||
c->cache_data.etag[i] == '\n'); --i)
c->cache_data.etag[i] = '\0';
} else if (14 < size && strncasecmp(data, "Last-Modified:", 14) == 0) {
/* extract Last-Modified header */
SKIP_ST(14);
if (i < size) {
c->cache_data.last_modified =
curl_getdate(&data[i], NULL);
}
}
return;
}
/**
* Generate an error page.
*
* \param c empty content to generate the page in
* \param error message to display
*/
void fetchcache_error_page(struct content *c, const char *error)
{
const char *params[] = { 0 };
int length;
if ((length = snprintf(error_page, sizeof(error_page),
messages_get("ErrorPage"), error)) < 0)
length = 0;
if (!content_set_type(c, CONTENT_HTML, "text/html", params))
return;
if (!content_process_data(c, error_page, length))
return;
content_convert(c, c->width, c->height);
/* Mark content as non-fresh, so it'll get cleaned from the
* cache at the earliest opportunity */
c->fresh = false;
}
/**
* Update a content's cache state
*
* \param c The content
*/
void fetchcache_cache_update(struct content *c)
{
if (c->cache_data.date == 0)
c->cache_data.date = time(NULL);
if (c->cache_data.no_cache)
c->fresh = false;
}
/**
* Clone cache info into a content
*
* \param c The content
* \param data Cache data
*/
void fetchcache_cache_clone(struct content *c,
const struct cache_data *data)
{
assert(c && data);
c->cache_data.req_time = data->req_time;
c->cache_data.res_time = data->res_time;
if (data->date != 0)
c->cache_data.date = data->date;
if (data->expires != 0)
c->cache_data.expires = data->expires;
if (data->age != INVALID_AGE)
c->cache_data.age = data->age;
if (data->max_age != INVALID_AGE)
c->cache_data.max_age = data->max_age;
if (data->no_cache)
c->cache_data.no_cache = data->no_cache;
if (data->etag) {
talloc_free(c->cache_data.etag);
c->cache_data.etag = talloc_strdup(c, data->etag);
}
if (data->last_modified)
c->cache_data.last_modified = data->last_modified;
}
/**
* Not modified callback handler
*/
void fetchcache_notmodified(struct content *c, const void *data)
{
struct content *fb;
union content_msg_data msg_data;
assert(c);
assert(c->status == CONTENT_STATUS_TYPE_UNKNOWN);
/* Look for cached content */
fb = content_get_ready(c->url);
if (fb) {
/* Found it */
intptr_t p1, p2;
void (*callback)(content_msg msg,
struct content *c, intptr_t p1,
intptr_t p2,
union content_msg_data data);
/* Now notify all users that we're changing content */
while (c->user_list->next) {
p1 = c->user_list->next->p1;
p2 = c->user_list->next->p2;
callback = c->user_list->next->callback;
if (!content_add_user(fb, callback, p1, p2)) {
c->type = CONTENT_UNKNOWN;
c->status = CONTENT_STATUS_ERROR;
msg_data.error = messages_get("NoMemory");
content_broadcast(c, CONTENT_MSG_ERROR,
msg_data);
return;
}
content_remove_user(c, callback, p1, p2);
msg_data.new_url = NULL;
callback(CONTENT_MSG_NEWPTR, fb, p1, p2, msg_data);
/* and catch user up with fallback's state */
if (fb->status == CONTENT_STATUS_LOADING) {
callback(CONTENT_MSG_LOADING,
fb, p1, p2, msg_data);
} else if (fb->status == CONTENT_STATUS_READY) {
callback(CONTENT_MSG_LOADING,
fb, p1, p2, msg_data);
if (content_find_user(fb, callback, p1, p2))
callback(CONTENT_MSG_READY,
fb, p1, p2, msg_data);
} else if (fb->status == CONTENT_STATUS_DONE) {
callback(CONTENT_MSG_LOADING,
fb, p1, p2, msg_data);
if (content_find_user(fb, callback, p1, p2))
callback(CONTENT_MSG_READY,
fb, p1, p2, msg_data);
if (content_find_user(fb, callback, p1, p2))
callback(CONTENT_MSG_DONE,
fb, p1, p2, msg_data);
} else if (fb->status == CONTENT_STATUS_ERROR) {
/* shouldn't usually occur */
msg_data.error = messages_get("MiscError");
callback(CONTENT_MSG_ERROR, fb, p1, p2,
msg_data);
}
}
/* mark content invalid */
c->fetch = 0;
c->status = CONTENT_STATUS_ERROR;
/* clone our cache control data into the fallback */
fetchcache_cache_clone(fb, &c->cache_data);
/* and update the fallback's cache state */
fetchcache_cache_update(fb);
}
else {
/* No cached content, so unconditionally refetch */
struct content_user *u;
const char *ref = fetch_get_referer(c->fetch);
const char *parent = fetch_get_parent_url(c->fetch);
char *referer = NULL;
char *parent_url = NULL;
if (ref) {
referer = strdup(ref);
if (!referer) {
c->type = CONTENT_UNKNOWN;
c->status = CONTENT_STATUS_ERROR;
msg_data.error = messages_get("NoMemory");
content_broadcast(c, CONTENT_MSG_ERROR,
msg_data);
return;
}
}
if (parent) {
parent_url = strdup(parent);
if (!parent_url) {
c->type = CONTENT_UNKNOWN;
c->status = CONTENT_STATUS_ERROR;
msg_data.error = messages_get("NoMemory");
content_broadcast(c, CONTENT_MSG_ERROR,
msg_data);
free(referer);
return;
}
}
fetch_abort(c->fetch);
c->fetch = 0;
c->cache_data.date = 0;
talloc_free(c->cache_data.etag);
c->cache_data.etag = 0;
for (u = c->user_list->next; u; u = u->next) {
fetchcache_go(c, referer, u->callback, u->p1, u->p2,
c->width, c->height, 0, 0,
false, parent_url);
}
free(parent_url);
free(referer);
}
}
/**
* Redirect callback handler
*/
void fetchcache_redirect(struct content *c, const void *data,
unsigned long size)
{
char *url, *url1;
char *referer, *parent_url;
long http_code;
const char *ref;
const char *parent;
bool can_fetch;
bool parent_was_verifiable;
union content_msg_data msg_data;
url_func_result result;
/* Preconditions */
assert(c && data);
assert(c->status == CONTENT_STATUS_TYPE_UNKNOWN);
/* Extract fetch details */
http_code = fetch_http_code(c->fetch);
ref = fetch_get_referer(c->fetch);
parent = fetch_get_parent_url(c->fetch);
parent_was_verifiable = fetch_get_verifiable(c->fetch);
/* Ensure a redirect happened */
assert(300 <= http_code && http_code <= 399);
/* 304 is handled by fetch_notmodified() */
assert(http_code != 304);
/* Clone referer and parent url
* originals are destroyed in fetch_abort() */
referer = ref ? strdup(ref) : NULL;
parent_url = parent ? strdup(parent) : NULL;
/* set the status to ERROR so that this content is
* destroyed in content_clean() */
fetch_abort(c->fetch);
c->fetch = 0;
c->status = CONTENT_STATUS_ERROR;
/* Ensure that referer cloning succeeded
* _must_ be after content invalidation */
if (ref && !referer) {
LOG(("Failed cloning referer"));
msg_data.error = messages_get("BadRedirect");
content_broadcast(c, CONTENT_MSG_ERROR, msg_data);
return;
}
/* Ensure parent url cloning succeeded
* _must_ be after content invalidation */
if (parent && !parent_url) {
LOG(("Failed cloning parent url"));
msg_data.error = messages_get("BadRedirect");
content_broadcast(c, CONTENT_MSG_ERROR, msg_data);
free(referer);
return;
}
/** \todo 300, 305, 307
* More specifically:
* + 300 needs to serve up the fetch body to the user
* + 305 needs to refetch using the proxy specified in ::data
* + 307 needs to refetch.
*
* If the original request method was either GET or HEAD, then follow
* redirect unconditionally. If the original request method was neither
* GET nor HEAD, then the user MUST be asked what to do.
*
* Note:
* For backwards compatibility, all 301, 302 and 303 redirects are
* followed unconditionally with a GET request to the new location.
*/
if (http_code != 301 && http_code != 302 && http_code != 303) {
LOG(("Unsupported redirect type %ld", http_code));
msg_data.error = messages_get("BadRedirect");
content_broadcast(c, CONTENT_MSG_ERROR, msg_data);
free(parent_url);
free(referer);
return;
}
/* Forcibly stop redirecting if we've followed too many redirects */
#define REDIRECT_LIMIT 10
if (c->redirect_count > REDIRECT_LIMIT) {
LOG(("Too many nested redirects"));
msg_data.error = messages_get("BadRedirect");
content_broadcast(c, CONTENT_MSG_ERROR, msg_data);
free(parent_url);
free(referer);
return;
}
#undef REDIRECT_LIMIT
/* redirect URLs must be absolute by HTTP/1.1, but many
* sites send relative ones: treat them as relative to
* requested URL */
result = url_join(data, c->url, &url1);
if (result != URL_FUNC_OK) {
msg_data.error = messages_get("BadRedirect");
content_broadcast(c, CONTENT_MSG_ERROR, msg_data);
free(parent_url);
free(referer);
return;
}
/* Normalize redirect target -- this is vital as this URL may
* be inserted into the urldb, which expects normalized URLs */
result = url_normalize(url1, &url);
if (result != URL_FUNC_OK) {
msg_data.error = messages_get("BadRedirect");
content_broadcast(c, CONTENT_MSG_ERROR, msg_data);
free(url1);
free(parent_url);
free(referer);
return;
}
/* No longer need url1 */
free(url1);
/* Determine if we've got a fetch handler for this url */
can_fetch = fetch_can_fetch(url);
/* Process users of this content */
while (c->user_list->next) {
intptr_t p1, p2;
void (*callback)(content_msg msg,
struct content *c, intptr_t p1,
intptr_t p2,
union content_msg_data data);
struct content *replacement;
p1 = c->user_list->next->p1;
p2 = c->user_list->next->p2;
callback = c->user_list->next->callback;
/* If we can't fetch this url, attempt to launch it */
if (!can_fetch) {
msg_data.launch_url = url;
callback(CONTENT_MSG_LAUNCH, c, p1, p2, msg_data);
}
/* Remove user */
content_remove_user(c, callback, p1, p2);
if (can_fetch) {
/* Get replacement content -- HTTP GET request */
/* A note about fetch verifiability: according to
* both RFC2109 and 2965, redirects result in an
* unverifiable fetch and thus cookies must be handled
* differently. Unfortunately, however, other browsers
* do not adhere to this rule and just process cookies
* as per normal in this case. Websites have come to
* depend upon this "feature", so we must do something
* which approximates the appropriate behaviour.
*
* Therefore, a redirected fetch will preserve the
* verifiability of the origin fetch. Thus, fetches
* for embedded objects will remain unverifiable,
* as expected.
*/
replacement = fetchcache(url, callback, p1, p2,
c->width, c->height, c->no_error_pages,
NULL, NULL, parent_was_verifiable,
c->download);
if (!replacement) {
msg_data.error = messages_get("BadRedirect");
content_broadcast(c, CONTENT_MSG_ERROR,
msg_data);
free(url);
free(parent_url);
free(referer);
return;
}
/* Set replacement's redirect count to 1 greater
* than ours */
replacement->redirect_count = c->redirect_count + 1;
/* Notify user that content has changed */
msg_data.new_url = url;
callback(CONTENT_MSG_NEWPTR, replacement,
p1, p2, msg_data);
/* Start fetching the replacement content */
fetchcache_go(replacement, referer, callback, p1, p2,
c->width, c->height, NULL, NULL,
parent_was_verifiable, parent_url);
}
}
/* Clean up */
free(url);
free(parent_url);
free(referer);
}
#ifdef TEST
#include <unistd.h>
void callback(fetchcache_msg msg, struct content *c, void *p, char *error)
{
switch (msg) {
case FETCHCACHE_OK:
LOG(("FETCHCACHE_OK, url '%s'", p));
break;
case FETCHCACHE_BADTYPE:
LOG(("FETCHCACHE_BADTYPE, url '%s'", p));
break;
case FETCHCACHE_ERROR:
LOG(("FETCHCACHE_ERROR, url '%s', error '%s'", p, error));
break;
default:
assert(0);
}
}
char *test[] = {"http://www.google.co.uk/", "http://www.ox.ac.uk/", "blah://blah/"};
int main(void)
{
int i;
cache_init();
fetch_init();
for (i = 0; i != sizeof(test) / sizeof(test[0]); i++)
fetchcache(test[i], 0, callback, test[i], 800, 0);
for (i = 0; i != 5; i++) {
fetch_poll();
sleep(1);
}
for (i = 0; i != sizeof(test) / sizeof(test[0]); i++)
fetchcache(test[i], 0, callback, test[i], 800, 0);
for (i = 0; i != 20; i++) {
fetch_poll();
sleep(1);
}
return 0;
}
#endif
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