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Return exceptions in requested feed formats (#841)

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* [Exceptions] Don't return header for bridge exceptions
* [Exceptions] Add link to list in exception message

This is an alternative when the button is not rendered
for some reason.

* [index] Don't return bridge exception for formats
* [index] Return feed item for bridge exceptions
* [BridgeAbstract] Rename 'getCacheTime' to 'getModifiedTime'
* [BridgeAbstract] Move caching to index.php to separate concerns

index.php needs more control over caching behavior in order to cache
exceptions. This cannot be done in a bridge, as the bridge might be
broken, thus preventing caching from working.

This also (and more importantly) separates concerns. The bridge should
not even care if caching is involved or not. Its purpose is to collect
and provide data.

Response times should be faster, as more complex bridge functions like
'setDatas' (evaluates all input parameters to predict the current
context) and 'collectData' (collects data from sites) can be skipped
entirely.

Notice: In its current form, index.php takes care of caching. This
could, however, be moved into a separate class (i.e. CacheAbstract)
in order to make implementation details cache specific.

* [index] Add '_error_time' parameter to $item['uri']

This ensures that error messages are recognized by feed readers as
new errors after 24 hours. During that time the same item is returned
no matter how often the cache is cleared.

References https://github.com/RSS-Bridge/rss-bridge/issues/814#issuecomment-420876162

* [index] Include '_error_time' in the title for errors

This prevents feed readers from "updating" feeds based on the title

* [index] Handle "HTTP_IF_MODIFIED_SINCE" client requests

Implementation is based on `BridgeAbstract::dieIfNotModified()`,
introduced in 422c125d8e and
simplified based on https://stackoverflow.com/a/10847262

Basically, before returning cached data we check if the client send
the "HTTP_IF_MODIFIED_SINCE" header. If the modification time is
more recent or equal to the cache time, we reply with "HTTP/1.1 304
 Not Modified" (same as before). Otherwise send the cached data.

* [index] Don't encode exception message with `htmlspecialchars`
* [Exceptions] Include error message in exception
* [index] Show different error message for error code 0
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LogMANOriginal 2018-10-15 17:21:43 +02:00 committed by GitHub
parent 996295e82f
commit b90bcee1fc
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4 changed files with 96 additions and 149 deletions
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96
index.php
View file

@ -178,14 +178,18 @@ try {
define('NOPROXY', true);
}
// Custom cache timeout
// Cache timeout
$cache_timeout = -1;
if(array_key_exists('_cache_timeout', $params)) {
if(!CUSTOM_CACHE_TIMEOUT) {
throw new \HttpException('This server doesn\'t support "_cache_timeout"!');
}
$cache_timeout = filter_var($params['_cache_timeout'], FILTER_VALIDATE_INT);
} else {
$cache_timeout = $bridge->getCacheTimeout();
}
// Remove parameters that don't concern bridges
@ -219,28 +223,90 @@ try {
$cache->purgeCache(86400); // 24 hours
$cache->setParameters($cache_params);
// Load cache & data
$items = array();
$infos = array();
$mtime = $cache->getTime();
if($mtime !== false
&& (time() - $cache_timeout < $mtime)
&& (!defined('DEBUG') || DEBUG !== true)) { // Load cached data
// Send "Not Modified" response if client supports it
// Implementation based on https://stackoverflow.com/a/10847262
if(isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
$stime = strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']);
if($mtime <= $stime) { // Cached data is older or same
header('HTTP/1.1 304 Not Modified');
die();
}
}
$cached = $cache->loadData();
if(isset($cached['items']) && isset($cached['extraInfos'])) {
$items = $cached['items'];
$infos = $cached['extraInfos'];
}
} else { // Collect new data
try {
$bridge->setCache($cache);
$bridge->setCacheTimeout($cache_timeout);
$bridge->dieIfNotModified();
$bridge->setDatas($bridge_params);
$bridge->collectData();
$items = $bridge->getItems();
$infos = array(
'name' => $bridge->getName(),
'uri' => $bridge->getURI(),
'icon' => $bridge->getIcon()
);
} catch(Error $e) {
http_response_code($e->getCode());
header('Content-Type: text/html');
die(buildBridgeException($e, $bridge));
$item = array();
// Create "new" error message every 24 hours
$params['_error_time'] = urlencode((int)(time() / 86400));
// Error 0 is a special case (i.e. "trying to get property of non-object")
if($e->getCode() === 0) {
$item['title'] = 'Bridge encountered an unexpected situation! (' . $params['_error_time'] . ')';
} else {
$item['title'] = 'Bridge returned error ' . $e->getCode() . '! (' . $params['_error_time'] . ')';
}
$item['uri'] = parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH) . '?' . http_build_query($params);
$item['timestamp'] = time();
$item['content'] = buildBridgeException($e, $bridge);
$items[] = $item;
} catch(Exception $e) {
http_response_code($e->getCode());
header('Content-Type: text/html');
die(buildBridgeException($e, $bridge));
$item = array();
// Create "new" error message every 24 hours
$params['_error_time'] = urlencode((int)(time() / 86400));
$item['uri'] = parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH) . '?' . http_build_query($params);
$item['title'] = 'Bridge returned error ' . $e->getCode() . '! (' . $params['_error_time'] . ')';
$item['timestamp'] = time();
$item['content'] = buildBridgeException($e, $bridge);
$items[] = $item;
}
// Store data in cache
$cache->saveData(array(
'items' => $items,
'extraInfos' => $infos
));
}
// Data transformation
try {
$format = Format::create($format);
$format->setItems($bridge->getItems());
$format->setExtraInfos($bridge->getExtraInfos());
$format->setLastModified($bridge->getCacheTime());
$format->setItems($items);
$format->setExtraInfos($infos);
$format->setLastModified($mtime);
$format->display();
} catch(Error $e) {
http_response_code($e->getCode());
@ -249,7 +315,7 @@ try {
} catch(Exception $e) {
http_response_code($e->getCode());
header('Content-Type: text/html');
die(buildBridgeException($e, $bridge));
die(buildTransformException($e, $bridge));
}
} else {
echo BridgeList::create($whitelist_selection, $showInactive);

99
lib/BridgeAbstract.php
View file

@ -9,23 +9,9 @@ abstract class BridgeAbstract implements BridgeInterface {
const CACHE_TIMEOUT = 3600;
const PARAMETERS = array();
protected $cache;
protected $extraInfos;
protected $items = array();
protected $inputs = array();
protected $queriedContext = '';
protected $cacheTimeout;
/**
* Return cachable datas (extrainfos and items) stored in the bridge
* @return mixed
*/
public function getCachable(){
return array(
'items' => $this->getItems(),
'extraInfos' => $this->getExtraInfos()
);
}
/**
* Return items stored in the bridge
@ -118,34 +104,18 @@ abstract class BridgeAbstract implements BridgeInterface {
/**
* Defined datas with parameters depending choose bridge
* Note : you can define a cache with "setCache"
* @param array array with expected bridge paramters
*/
public function setDatas(array $inputs){
if(!is_null($this->cache)) {
$time = $this->cache->getTime();
if($time !== false
&& (time() - $this->getCacheTimeout() < $time)
&& (!defined('DEBUG') || DEBUG !== true)) {
$cached = $this->cache->loadData();
if(isset($cached['items']) && isset($cached['extraInfos'])) {
$this->items = $cached['items'];
$this->extraInfos = $cached['extraInfos'];
return;
}
}
}
if(empty(static::PARAMETERS)) {
if(!empty($inputs)) {
returnClientError('Invalid parameters value(s)');
}
$this->collectData();
if(!is_null($this->cache)) {
$this->cache->saveData($this->getCachable());
}
return;
}
$validator = new ParameterValidator();
@ -172,11 +142,6 @@ abstract class BridgeAbstract implements BridgeInterface {
$this->setInputs($inputs, $this->queriedContext);
$this->collectData();
if(!is_null($this->cache)) {
$this->cache->saveData($this->getCachable());
}
}
/**
@ -201,20 +166,10 @@ abstract class BridgeAbstract implements BridgeInterface {
}
public function getName(){
// Return cached name when bridge is using cached data
if(isset($this->extraInfos)) {
return $this->extraInfos['name'];
}
return static::NAME;
}
public function getIcon(){
// Return cached icon when bridge is using cached data
if(isset($this->extraInfos)) {
return $this->extraInfos['icon'];
}
return '';
}
@ -223,59 +178,11 @@ abstract class BridgeAbstract implements BridgeInterface {
}
public function getURI(){
// Return cached uri when bridge is using cached data
if(isset($this->extraInfos)) {
return $this->extraInfos['uri'];
}
return static::URI;
}
public function getExtraInfos(){
return array(
'name' => $this->getName(),
'uri' => $this->getURI(),
'icon' => $this->getIcon()
);
}
public function setCache(\CacheInterface $cache){
$this->cache = $cache;
}
public function setCacheTimeout($timeout){
if(is_numeric($timeout) && ($timeout < 1 || $timeout > 86400)) {
$this->cacheTimeout = static::CACHE_TIMEOUT;
return;
}
$this->cacheTimeout = $timeout;
}
public function getCacheTimeout(){
return isset($this->cacheTimeout) ? $this->cacheTimeout : static::CACHE_TIMEOUT;
return static::CACHE_TIMEOUT;
}
public function getCacheTime(){
return !is_null($this->cache) ? $this->cache->getTime() : false;
}
public function dieIfNotModified(){
if ((defined('DEBUG') && DEBUG === true)) return; // disabled in debug mode
$if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ? $_SERVER['HTTP_IF_MODIFIED_SINCE'] : false;
if (!$if_modified_since) return; // If-Modified-Since value is required
$last_modified = $this->getCacheTime();
if (!$last_modified) return; // did not detect cache time
if (time() - $this->getCacheTimeout() > $last_modified) return; // cache timeout
$last_modified = (gmdate('D, d M Y H:i:s ', $last_modified) . 'GMT');
if ($if_modified_since == $last_modified) {
header('HTTP/1.1 304 Not Modified');
die();
}
}
}

30
lib/BridgeInterface.php
View file

@ -6,13 +6,6 @@ interface BridgeInterface {
*/
public function collectData();
/**
* Returns an array of cachable elements
*
* @return array Associative array of cachable elements
*/
public function getCachable();
/**
* Returns the description
*
@ -20,13 +13,6 @@ interface BridgeInterface {
*/
public function getDescription();
/**
* Return an array of extra information
*
* @return array Associative array of extra information
*/
public function getExtraInfos();
/**
* Returns an array of collected items
*
@ -69,22 +55,6 @@ interface BridgeInterface {
*/
public function getURI();
/**
* Sets the cache instance
*
* @param object CacheInterface The cache instance
*/
public function setCache(\CacheInterface $cache);
/**
* Sets the timeout for clearing the cache files. The timeout must be
* specified between 1..86400 seconds (max. 24 hours). The default timeout
* (specified by the bridge maintainer) applies for invalid values.
*
* @param int $timeout The cache timeout in seconds
*/
public function setCacheTimeout($timeout);
/**
* Returns the cache timeout
*

12
lib/Exceptions.php
View file

@ -69,14 +69,18 @@ function buildBridgeException($e, $bridge){
. Configuration::getVersion()
. '`';
$body_html = nl2br($body);
$link = buildGitHubIssueQuery($title, $body, 'bug report', $bridge->getMaintainer());
$header = buildHeader($e, $bridge);
$message = "<strong>{$bridge->getName()}</strong> was
unable to receive or process the remote website's content!";
$message = <<<EOD
<strong>{$bridge->getName()}</strong> was unable to receive or process the
remote website's content!<br>
{$body_html}
EOD;
$section = buildSection($e, $bridge, $message, $link);
return buildPage($title, $header, $section);
return $section;
}
/**
@ -127,7 +131,7 @@ function buildSection($e, $bridge, $message, $link){
<ul class="advice">
<li>Press Return to check your input parameters</li>
<li>Press F5 to retry</li>
<li>Open a GitHub Issue if this error persists</li>
<li>Open a <a href="{$link}">GitHub Issue</a> if this error persists</li>
</ul>
</div>
<a href="{$link}" title="After clicking this button you can review