Merge pull request rollbar#186 from ArturMoczulski/github-137-inject-…

…rollbarjs

Github Issue rollbar#137: Add helper function to inject javascript snippet in views

README.md

@@ -128,6 +128,39 @@ Rollbar::init(array(
 ?>
 ```
 
+## Integration with Rollbar.js
+
+In case you want to report your JavaScript errors using [Rollbar.js](https://github.com/rollbar/rollbar.js), you can configure the SDK to enable Rollbar.js on your site. Example:
+
+```php
+$rollbarJs = Rollbar\RollbarJsHelper::buildJs(
+    array(
+        "accessToken" => "POST_CLIENT_ITEM_ACCESS_TOKEN",
+        "captureUncaught" => true,
+        "payload" => array(
+            "environment" => "production"
+        ),
+        /* other configuration you want to pass to RollbarJS */
+    )
+);
+```
+
+Or if you are using Content-Security-Policy: script-src 'unsafe-inline'
+```php
+$rollbarJs = Rollbar\RollbarJsHelper::buildJs(
+    array(
+        "accessToken" => "POST_CLIENT_ITEM_ACCESS_TOKEN",
+        "captureUncaught" => true,
+        "payload" => array(
+            "environment" => "production"
+        ),
+        /* other configuration you want to pass to RollbarJS */
+    ),
+    headers_list(),
+    $yourNonceString
+);
+```
+
 ## Basic Usage
 
 That's it! Uncaught errors and exceptions will now be reported to Rollbar.

src/RollbarJsHelper.php

@@ -0,0 +1,170 @@
+<?php namespace Rollbar;
+
+class RollbarJsHelper
+{
+
+    protected $config;
+
+    /**
+     * @param array $config The array passed to he should have the same
+     * available options that you can find in Rollbar.js, using symbols or
+     * strings for the keys.
+     */
+    public function __construct($config)
+    {
+        $this->config = $config;
+    }
+
+    /**
+     * Shortcut method for building the RollbarJS Javascript
+     *
+     * @param array $config @see addJs()
+     * @param string $nonce @see addJs()
+     *
+     * @return string
+     */
+    public static function buildJs($config, $headers = null, $nonce = null)
+    {
+        $helper = new self($config);
+        return $helper->addJs($headers, $nonce);
+    }
+
+    /**
+     * Build Javascript required to include RollbarJS on
+     * an HTML page
+     *
+     * @param array $headers Response headers usually retrieved through
+     * headers_list() used to verify if nonce should be added to script
+     * tags based on Content-Security-Policy
+     * @param string $nonce Content-Security-Policy nonce string if exists
+     *
+     * @return string
+     */
+    public function addJs($headers = null, $nonce = null)
+    {
+        return $this->scriptTag(
+            $this->configJsTag() .$this->jsSnippet(),
+            $headers,
+            $nonce
+        );
+    }
+
+    /**
+     * Build RollbarJS config script
+     *
+     * @return string
+     */
+    public function configJsTag()
+    {
+        $config = isset($this->config['options']) ? $this->config['options'] : new \stdClass();
+        return "var _rollbarConfig = " . json_encode($config) . ";";
+    }
+
+    /**
+     * Build rollbar.snippet.js string
+     *
+     * @return string
+     */
+    public function jsSnippet()
+    {
+        return file_get_contents(
+            $this->snippetPath()
+        );
+    }
+
+    /**
+     * @return string Path to the rollbar.snippet.js
+     */
+    public function snippetPath()
+    {
+        return realpath(__DIR__ . "/../data/rollbar.snippet.js");
+    }
+
+    /**
+     * Should JS snippet be added to the HTTP response
+     *
+     * @param int $status
+     * @param array $headers
+     *
+     * @return boolean
+     */
+    public function shouldAddJs($status, $headers)
+    {
+        return
+            $status == 200 &&
+            $this->isHtml($headers) &&
+            !$this->hasAttachment($headers);
+
+            /**
+             * @todo not sure if below two conditions will be applicable
+             */
+            /* !env[JS_IS_INJECTED_KEY] */
+            /* && !streaming?(env) */
+    }
+
+    /**
+     * Is the HTTP response a valid HTML response
+     *
+     * @param array $headers
+     *
+     * @return boolean
+     */
+    public function isHtml($headers)
+    {
+        return in_array('Content-Type: text/html', $headers);
+    }
+
+    /**
+     * Does the HTTP response include an attachment
+     *
+     * @param array $headers
+     *
+     * @return boolean
+     */
+    public function hasAttachment($headers)
+    {
+        return in_array('Content-Disposition: attachment', $headers);
+    }
+
+    /**
+     * Is `nonce` attribute on the script tag needed?
+     *
+     * @param array $headers
+     *
+     * @return boolean
+     */
+    public function shouldAppendNonce($headers)
+    {
+        foreach ($headers as $header) {
+            if (strpos($header, 'Content-Security-Policy') !== false &&
+                strpos($header, "'unsafe-inline'") !== false) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Build safe HTML script tag
+     *
+     * @param string $content
+     * @param array $headers
+     * @param
+     *
+     * @return string
+     */
+    public function scriptTag($content, $headers = null, $nonce = null)
+    {
+        if ($headers !== null && $this->shouldAppendNonce($headers)) {
+            if (!$nonce) {
+                throw new \Exception('Content-Security-Policy is script-src '.
+                                     'inline-unsafe but nonce value not provided.');
+            }
+
+            return "\n<script type=\"text/javascript\" nonce=\"$nonce\">$content</script>";
+        } else {
+            return "\n<script type=\"text/javascript\">$content</script>";
+        }
+    }
+}