Introduction to Helpers

The file helpers.php contains a cornucopia of useful helper functions to assist feather and module development. Each function is fully documented in the source file.

Sessions

Name	Description
`logged_in()`	Returns whether or not the visitor is logged in.
`authenticate()`	Generates or validates an authentication token for the session.

Routing

Name	Description
`redirect()`	Redirects to the supplied URL and exits immediately.
`show_403()`	Shows an error message with a 403 HTTP header.
`show_404()`	Shows an error message with a 404 HTTP header.
`url()`	Generate the canonical URL^[note] for an action e.g. `url('login')`.
`self_url()`	Returns an absolute URL^[note] for the current request.

Localization

Name	Description
`lang_code()`	Converts a language code to a localised display name.
`lang_base()`	Extracts the primary language subtag for the supplied code.
`__()`	Translates a string using PHP-gettext.
`_f()`	Translates a string with `sprintf()` formatting.
`_p()`	Translates a plural (or not) form of a string.
`_w()`	Formats and internationalizes a string that isn't a regular time() value.

See also: Localizing Extensions.

Time/Date

Name	Description
`when()`	Formats a string that isn't a regular `time()` value.
`datetime()`	Formats datetime for SQL queries.
`now()`	Alias to `strtotime()`, for prettiness like `now("+1 day")`.
`convert_datetime()`	Converts datetime formatting from PHP to ICU format.

Variable Manipulation

Name	Description
`fallback()`	Sets the supplied variable if it is not already set.
`oneof()`	Returns a value from the supplied set of arguments.
`derezz()`	Strips tags from the supplied variable and tests it for emptiness.
`token()`	Salt and hash a unique token using the supplied data.
`crc24()`	Performs a 24-bit cyclic redundancy check.
`slug()`	Generates a random slug value for posts and pages.
`random()`	Generates a string of alphanumeric random characters.
`shorthand_bytes()`	Decode shorthand bytes notation from php.ini.
`match_any()`	Try to match a string against an array of regular expressions.
`keywords()`	Parse keyword searches for values in specific database columns.

String Manipulation

Name	Description
`pluralize()`	Pluralizes a word.
`depluralize()`	Singularizes a word.
`normalize()`	Attempts to normalize all newlines and whitespace into single spaces.
`camelize()`	Converts a string to camel-case.
`decamelize()`	Undoes camel-case conversion.
`truncate()`	Truncates a string to the requested number of characters or less.
`markdown()`	Implements the Markdown content parsing filter.
`emote()`	Converts emoticons to Unicode emoji HTML entities.
`fix()`	Neutralizes HTML and quotes in strings for display.
`unfix()`	Undoes neutralization of HTML and quotes in strings.
`sanitize()`	Sanitizes a string of troublesome characters, typically for use in URLs.
`sanitize_html()`	Sanitize HTML to disable scripts and obnoxious attributes.

Remote Fetches

Name	Description
`get_remote()`	Retrieve the contents of a URL.
`grab_urls()`	Crawls a string and grabs hyperlinks from it.
`merge_urls()`	Combines a base URL and relative path into a target URL.

Modules and Feathers

Name	Description
`module_enabled()`	Determines if a module is currently enabled and not cancelled.
`feather_enabled()`	Determines if a feather is currently enabled and not cancelled.
`cancel_module()`	Temporarily declares a module cancelled (disabled).
`cancel_feather()`	Temporarily declares a feather cancelled (disabled).

Upload Management

Name	Description
`upload()`	Validates and moves an uploaded file to the uploads directory.
`upload_from_url()`	Copies a file from a remote URL to the uploads directory.
`uploaded()`	Generates an absolute URL^[note] or filesystem path to an uploaded file.
`uploaded_search()`	Returns an array of files discovered in the uploads directory.
`upload_tester()`	Tests uploaded file information to determine if the upload was successful.
`upload_filename()`	Generates a sanitized unique name for an uploaded file.
`upload_filter_whitelist()`	Returns an array containing a default list of allowed file extensions.
`delete_upload()`	Deletes an uploaded file.

Input Validation and Processing

Name	Description
`password_strength()`	Award a numeric score for the strength of a password. `passwordStrength()` is the client-side equivalent.
`is_url()`	Does the string look like a web URL? `isURL()` is the client-side equivalent.
`add_scheme()`	Prefixes a URL with a scheme if none was detected. `addScheme()` is the client-side equivalent.
`is_email()`	Does the string look like an email address? `isEmail()` is the client-side equivalent.
`generate_captcha()`	Generates a captcha form element.
`check_captcha`	Checks the response to a captcha.
`get_gravatar()`	Get either a Gravatar URL or complete image tag for a specified email address.

Responding to Requests

Name	Description
`json_set()`	JSON encodes a value and checks for errors.
`json_get()`	JSON decodes a value and checks for errors.
`json_response()`	Send a structured JSON response.
`file_attachment()`	Send a file attachment to the visitor.
`zip_archive()`	Creates a basic flat Zip archive from an array of items.
`email()`	Sends an email using PHP's `mail()` function or an alternative.

See also: Adding Ajax Functionality.