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diff --git a/docs/reference.md b/docs/reference.md new file mode 100644 index 0000000..8153ebe --- /dev/null +++ b/docs/reference.md @@ -0,0 +1,269 @@ +title: Library Reference + +# Using Markdown as a Python Library + +First and foremost, Python-Markdown is intended to be a python library module +used by various projects to convert Markdown syntax into HTML. + +## The Basics + +To use markdown as a module: + +```python +import markdown +html = markdown.markdown(your_text_string) +``` + +## The Details + +Python-Markdown provides two public functions ([`markdown.markdown`](#markdown) +and [`markdown.markdownFromFile`](#markdownFromFile)) both of which wrap the +public class [`markdown.Markdown`](#Markdown). If you're processing one +document at a time, these functions will serve your needs. However, if you need +to process multiple documents, it may be advantageous to create a single +instance of the `markdown.Markdown` class and pass multiple documents through +it. If you do use a single instance though, make sure to call the `reset` +method appropriately ([see below](#convert)). + +### markdown.markdown(text [, **kwargs]) {: #markdown data-toc-label='markdown.markdown' } + +The following options are available on the `markdown.markdown` function: + +__text__{: #text } + +: The source Unicode string. (required) + + !!! note "Important" + Python-Markdown expects a **Unicode** string as input (some simple ASCII binary strings *may* work only by + coincidence) and returns output as a Unicode string. Do not pass binary strings to it! If your input is + encoded, (e.g. as UTF-8), it is your responsibility to decode it. For example: + + :::python + with open("some_file.txt", "r", encoding="utf-8") as input_file: + text = input_file.read() + html = markdown.markdown(text) + + If you want to write the output to disk, you *must* encode it yourself: + + :::python + with open("some_file.html", "w", encoding="utf-8", errors="xmlcharrefreplace") as output_file: + output_file.write(html) + +__extensions__{: #extensions } + +: A list of extensions. + + Python-Markdown provides an [API](extensions/api.md) for third parties to + write extensions to the parser adding their own additions or changes to the + syntax. A few commonly used extensions are shipped with the markdown + library. See the [extension documentation](extensions/index.md) for a + list of available extensions. + + The list of extensions may contain instances of extensions and/or strings + of extension names. + + :::python + extensions=[MyExtClass(), 'myext', 'path.to.my.ext:MyExtClass'] + + !!! note + The preferred method is to pass in an instance of an extension. Strings + should only be used when it is impossible to import the Extension Class + directly (from the command line or in a template). + + When passing in extension instances, each class instance must be a subclass + of `markdown.extensions.Extension` and any configuration options should be + defined when initiating the class instance rather than using the + [`extension_configs`](#extension_configs) keyword. For example: + + :::python + from markdown.extensions import Extension + class MyExtClass(Extension): + # define your extension here... + + markdown.markdown(text, extensions=[MyExtClass(option='value')]) + + If an extension name is provided as a string, the string must either be the + registered entry point of any installed extension or the importable path + using Python's dot notation. + + See the documentation specific to an extension for the string name assigned + to an extension as an entry point. Simply include the defined name as + a string in the list of extensions. For example, if an extension has the + name `myext` assigned to it and the extension is properly installed, then + do the following: + + :::python + markdown.markdown(text, extensions=['myext']) + + If an extension does not have a registered entry point, Python's dot + notation may be used instead. The extension must be installed as a + Python module on your PYTHONPATH. Generally, a class should be specified in + the name. The class must be at the end of the name and be separated by a + colon from the module. + + Therefore, if you were to import the class like this: + + :::python + from path.to.module import MyExtClass + + Then load the extension as follows: + + :::python + markdown.markdown(text, extensions=['path.to.module:MyExtClass']) + + If only one extension is defined within a module and the module includes a + `makeExtension` function which returns an instance of the extension, then + the class name is not necessary. For example, in that case one could do + `extensions=['path.to.module']`. Check the documentation for a specific + extension to determine if it supports this feature. + + When loading an extension by name (as a string), you can only pass in + configuration settings to the extension by using the + [`extension_configs`](#extension_configs) keyword. + + !!! seealso "See Also" + See the documentation of the [Extension API](extensions/api.md) for + assistance in creating extensions. + +__extension_configs__{: #extension_configs } + +: A dictionary of configuration settings for extensions. + + Any configuration settings will only be passed to extensions loaded by name + (as a string). When loading extensions as class instances, pass the + configuration settings directly to the class when initializing it. + + !!! Note + The preferred method is to pass in an instance of an extension, which + does not require use of the `extension_configs` keyword at all. + See the [extensions](#extensions) keyword for details. + + The dictionary of configuration settings must be in the following format: + + :::python + extension_configs = { + 'extension_name_1': { + 'option_1': 'value_1', + 'option_2': 'value_2' + }, + 'extension_name_2': { + 'option_1': 'value_1' + } + } + + When specifying the extension name, be sure to use the exact same + string as is used in the [extensions](#extensions) keyword to load the + extension. Otherwise, the configuration settings will not be applied to + the extension. In other words, you cannot use the entry point in on + place and Python dot notation in the other. While both may be valid for + a given extension, they will not be recognized as being the same + extension by Markdown. + + See the documentation specific to the extension you are using for help in + specifying configuration settings for that extension. + +__output_format__{: #output_format }: + +: Format of output. + + Supported formats are: + + * `"xhtml"`: Outputs XHTML style tags. **Default**. + * `"html5"`: Outputs HTML style tags. + + The values can be in either lowercase or uppercase. + +__tab_length__{: #tab_length }: + +: Length of tabs in the source. Default: 4 + +### `markdown.markdownFromFile (**kwargs)` {: #markdownFromFile data-toc-label='markdown.markdownFromFile' } + +With a few exceptions, `markdown.markdownFromFile` accepts the same options as +`markdown.markdown`. It does **not** accept a `text` (or Unicode) string. +Instead, it accepts the following required options: + +__input__{: #input } (required) + +: The source text file. + + `input` may be set to one of three options: + + * a string which contains a path to a readable file on the file system, + * a readable file-like object, + * or `None` (default) which will read from `stdin`. + +__output__{: #output } + +: The target which output is written to. + + `output` may be set to one of three options: + + * a string which contains a path to a writable file on the file system, + * a writable file-like object, + * or `None` (default) which will write to `stdout`. + +__encoding__{: #encoding } + +: The encoding of the source text file. + + Defaults to `"utf-8"`. The same encoding will always be used for input and output. + The `xmlcharrefreplace` error handler is used when encoding the output. + + !!! Note + This is the only place that decoding and encoding of Unicode + takes place in Python-Markdown. If this rather naive solution does not + meet your specific needs, it is suggested that you write your own code + to handle your encoding/decoding needs. + +### markdown.Markdown([**kwargs]) {: #Markdown data-toc-label='markdown.Markdown' } + +The same options are available when initializing the `markdown.Markdown` class +as on the [`markdown.markdown`](#markdown) function, except that the class does +**not** accept a source text string on initialization. Rather, the source text +string must be passed to one of two instance methods. + +!!! warning + + Instances of the `markdown.Markdown` class are only thread safe within + the thread they were created in. A single instance should not be accessed + from multiple threads. + +#### Markdown.convert(source) {: #convert data-toc-label='Markdown.convert' } + +The `source` text must meet the same requirements as the [`text`](#text) +argument of the [`markdown.markdown`](#markdown) function. + +You should also use this method if you want to process multiple strings +without creating a new instance of the class for each string. + +```python +md = markdown.Markdown() +html1 = md.convert(text1) +html2 = md.convert(text2) +``` + +Depending on which options and/or extensions are being used, the parser may +need its state reset between each call to `convert`. + +```python +html1 = md.convert(text1) +md.reset() +html2 = md.convert(text2) +``` + +To make this easier, you can also chain calls to `reset` together: + +```python +html3 = md.reset().convert(text3) +``` + +#### Markdown.convertFile(**kwargs) {: #convertFile data-toc-label='Markdown.convertFile' } + +The arguments of this method are identical to the arguments of the same +name on the `markdown.markdownFromFile` function ([`input`](#input), +[`output`](#output), and [`encoding`](#encoding)). As with the +[`convert`](#convert) method, this method should be used to +process multiple files without creating a new instance of the class for +each document. State may need to be `reset` between each call to +`convertFile` as is the case with `convert`. |