# 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:

    import markdown
    html = markdown.markdown(your_text_string)

## The Details

Python-Markdown provides two public functions (`markdown.markdown` and `markdown.markdownFromFile`) both of which wrap the public class `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).

### markdown.markdown(text [, **kwargs])

The following options are available on the `markdown.markdown` function:

text

  The source Unicode string. (required)

  Important

  Python-Markdown expects Unicode as input (although some simple ASCII strings may work) and returns output as Unicode. Do not pass encoded strings to it! If your input is encoded, (e.g. as UTF-8), it is your responsibility to decode it. For example:

      input_file = codecs.open("some_file.txt", mode="r", encoding="utf-8")
      text = input_file.read()
      html = markdown.markdown(text)

  If you want to write the output to disk, you must encode it yourself:

      output_file = codecs.open("some_file.html", "w",
                                encoding="utf-8",
                                errors="xmlcharrefreplace"
      )
      output_file.write(html)

extensions

  A list of extensions.

  Python-Markdown provides an API 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 for a list of available extensions.

  The list of extensions may contain instances of extensions and/or strings of extension names.

      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` keyword. For example:

      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:

      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:

      from path.to.module import MyExtClass

  Then load the extension as follows:

      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` keyword.

  See Also

  See the documentation of the Extension API for assistance in creating extensions.

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 keyword for details.

  The dictionary of configuration settings must be in the following format:

      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 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:

  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:

  Length of tabs in the source. Default: 4

### `markdown.markdownFromFile (**kwargs)`

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 (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

  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

  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])

The same options are available when initializing the `markdown.Markdown` class as on the `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:

#### Markdown.convert(source)

The `source` text must meet the same requirements as the `text` argument of the `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.

    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`, otherwise performance can degrade drastically:

    html1 = md.convert(text1)
    md.reset()
    html2 = md.convert(text2)

To make this easier, you can also chain calls to `reset` together:

    html3 = md.reset().convert(text3)

#### Markdown.convertFile(**kwargs)

The arguments of this method are identical to the arguments of the same name on the `markdown.markdownFromFile` function (`input`, `output`, and `encoding`). As with the `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`.