# Helper functions - RSS-Bridge
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# Helper functions

November 3, 2023 at 9:42 AM Edit on GitHub

# #getInput

The `getInput` function is used to receive a value for a parameter, specified in `const PARAMETERS`

    $this->getInput('your input name here');

`getInput` will either return the value for your parameter or `null` if the parameter is unknown or not specified.

# #getKey

The `getKey` function is used to receive the key name to a selected list value given the name of the list, specified in `const PARAMETERS` Is able to work with multidimensional list arrays.

    // Given a multidimensional array like this
    const PARAMETERS = [[
            'country' => [
                'name' => 'Country',
                'type' => 'list',
                'values' => [
                    'North America' => [
                        'Mexico' => 'mx',
                        'United States' => 'us'
                    ],
                    'South America' => [
                        'Uruguay' => 'uy',
                        'Venezuela' => 've'
                    ],
                ]
            ]
    ]],
    // Provide the list name to the function
    $this->getKey('country');
    // if the selected value was "ve", this function will return "Venezuela"

`getKey` will either return the key name for your parameter or `null` if the parameter is unknown or not specified.

# #getContents

The `getContents` function uses cURL to acquire data from the specified URI while respecting the various settings defined at a global level by RSS-Bridge (i.e., proxy host, user agent, etc.). This function accepts a few parameters:

Parameter | Type | Optional | Description
--- | --- | --- | ---
`url` | string | required | The URL of the contents to acquire
`header` | array | optional | An array of HTTP header fields to set, in the format `array('Content-type: text/plain', 'Content-length: 100')`, see CURLOPT_HTTPHEADER
`opts` | array | optional | An array of cURL options in the format `array(CURLOPT_POST => 1);`, see curl_setopt for a complete list of options.
`returnFull` | boolean | optional | Specifies whether to return the response body from cURL (default) or the response body, code, headers, etc.

    $header = array('Content-type:text/plain', 'Content-length: 100');
    $opts = array(CURLOPT_POST => 1);
    $html = getContents($url, $header, $opts);

# #getSimpleHTMLDOM

The `getSimpleHTMLDOM` function is a wrapper for the simple_html_dom file_get_html function in order to provide context by design.

    $html = getSimpleHTMLDOM('your URI');

# #getSimpleHTMLDOMCached

The `getSimpleHTMLDOMCached` function does the same as the `getSimpleHTMLDOM` function, except that the content received for the given URI is stored in a cache and loaded from cache on the next request if the specified cache duration was not reached.

Use this function for data that is very unlikely to change between consecutive requests to RSS-Bridge. This function allows to specify the cache duration with the second parameter.

    $html = getSimpleHTMLDOMCached('your URI', 86400); // Duration 24h

# #returnClientError

The `returnClientError` function aborts execution of the current bridge and returns the given error message with error code 400:

    returnClientError('Your error message')

Use this function when the user provided invalid parameter or a required parameter is missing.

# #returnServerError

The `returnServerError` function aborts execution of the current bridge and returns the given error message with error code 500:

    returnServerError('Your error message')

Use this function when a problem occurs that has nothing to do with the parameters provided by the user. (like: Host service gone missing, empty data received, etc…)

# #defaultLinkTo

Automatically replaces any relative URL in a given string or DOM object (i.e. the one returned by getSimpleHTMLDOM) with an absolute URL.

    defaultLinkTo ( mixed $content, string $server ) : object

Returns a DOM object (even if provided a string).

Remarks

- Only handles `<a>` and `<img>` tags.

Example

    $html = '<img src="/blob/master/README.md">';

    $html = defaultLinkTo($html, 'https://www.github.com/rss-bridge/rss-bridge'); // Using custom server
    $html = defaultLinkTo($html, $this->getURI()); // Using bridge URL

    // Output
    // <img src="https://www.github.com/rss-bridge/rss-bridge/blob/master/README.md">

# #backgroundToImg

Replaces tags with styles of `backgroud-image` by `<img />` tags.

    backgroundToImg(mixed $htmlContent) : object

Returns a DOM object (even if provided a string).

# #extractFromDelimiters

Extract the first part of a string matching the specified start and end delimiters.

    function extractFromDelimiters(string $string, string $start, string $end) : mixed

Returns the extracted string if delimiters were found and false otherwise.

Example

    $string = '<div>Post author: John Doe</div>';
    $start = 'author: ';
    $end = '<';
    $extracted = extractFromDelimiters($string, $start, $end);

    // Output
    // 'John Doe'

# #stripWithDelimiters

Remove one or more part(s) of a string using a start and end delimiter. It is the inverse of `extractFromDelimiters`.

    function stripWithDelimiters(string $string, string $start, string $end) : string

Returns the cleaned string, even if no delimiters were found.

Example

    $string = 'foo<script>superscript()</script>bar';
    $start = '<script>';
    $end = '</script>';
    $cleaned = stripWithDelimiters($string, $start, $end);

    // Output
    // 'foobar'

# #stripRecursiveHTMLSection

Remove HTML sections containing one or more sections using the same HTML tag.

    function stripRecursiveHTMLSection(string $string, string $tag_name, string $tag_start) : string

Example

    $string = 'foo<div class="ads"><div>ads</div>ads</div>bar';
    $tag_name = 'div';
    $tag_start = '<div class="ads">';
    $cleaned = stripRecursiveHTMLSection($string, $tag_name, $tag_start);

    // Output
    // 'foobar'

# #markdownToHtml

Converts markdown input to HTML using Parsedown.

Parameter | Type | Optional | Description
--- | --- | --- | ---
`string` | string | required | The URL of the contents to acquire
`config` | array | optional | An array of Parsedown options in the format `['breaksEnabled' => true]`

Valid options:

Option | Default | Description
--- | --- | ---
`breaksEnabled` | `false` | Enable automatic line breaks
`markupEscaped` | `false` | Escape inline markup (HTML)
`urlsLinked` | `true` | Automatically convert URLs to links

    function markdownToHtml(string $string, array $config = []) : string

Example

    $input = <<<EOD
    RELEASE-2.8
     * Share QR code of a token
     * Dark mode improvemnet
     * Fix some layout issues
     * Add shortcut to launch the app with screenshot mode on
     * Translation improvements
    EOD;
    $html = markdownToHtml($input);

    // Output:
    // <p>RELEASE-2.8</p>
    // <ul>
    // <li>Share QR code of a token</li>
    // <li>Dark mode improvemnet</li>
    // <li>Fix some layout issues</li>
    // <li>Add shortcut to launch the app with screenshot mode on</li>
    // <li>Translation improvements</li>
    // </ul>