MarkdownSnippets

A dotnet tool or MsBuild Task that extract snippets from code files and merges them into markdown documents.

See Milestones for release notes.

.net 8 or higher is required to run the dotnet tool.

Value Proposition

Automatically extract snippets from code and injecting them into markdown documents has several benefits:

Snippets can be verified by a compiler or parser.
Tests can be run on snippets, or snippets can be pulled from existing tests.
Changes in code are automatically reflected in documentation.
Snippets are less likely to get out of sync with the main code-base.
Snippets in markdown is easier to create and maintain since any preferred editor can be used to edit them.

Behavior

Recursively scan the target directory for code files containing snippets. (See exclusion).
Recursively scan the target directory for markdown (.md or mdx) files. (See Document Scanning).
Merge the snippets into those markdown files.

Installation

Ensure dotnet CLI is installed.

Install MarkdownSnippets.Tool

dotnet tool install -g MarkdownSnippets.Tool

See also: MsBuild Task usage

Usage

mdsnippets C:\Code\TargetDirectory

If no directory is passed the current directory will be used, but only if it exists with a git repository directory tree. If not an error is returned.

Document Convention

There are two approaches scanning and modifying markdown files.

SourceTransform

This is the default.

source.md file

The file convention recursively scans the target directory for all *.source.md files. Once snippets are merged the .source.md to produce .md files. So for example readme.source.md would be merged with snippets to produce readme.md. Note that this process will overwrite any existing .md files that have matching .source.md files.

mdsource directory

There is a secondary convention that leverages the use of a directory named mdsource. Where .source.md files are placed in a mdsource sub-directory, the mdsource part of the file path will be removed when calculating the target path. This allows the .source.md to be grouped in a sub directory and avoid cluttering up the main documentation directory.

When using the mdsource convention, all references to other files, such as links and images, should specify the full path from the root of the repository. This will allow those links to work correctly in both the source and generated markdown files. Relative paths cannot work for both the source and the target file.

InPlaceOverwrite

Recursively scans the target directory for all *.md files and merges snippets into those files.

Command line

mdsnippets -c InPlaceOverwrite

mdsnippets --convention InPlaceOverwrite

Config file

Can be enabled in mdsnippets.json config file.

{
  "Convention": "InPlaceOverwrite"
}

Moving from SourceTransform to InPlaceOverwrite

Ensure "WriteHeader": false is used in mdsnippets.json.
Ensure "ReadOnly": false is used in mdsnippets.json.
Ensure using the current stable version and a docs generation has run.
Delete all .source.md files.
Modify mdsnippets.json to add "Convention": "InPlaceOverwrite".
Run the docs generation.

Mark resulting files as read only

To mark the resulting documents files as read only use -r or --read-only.

This can be helpful in preventing incorrectly editing the documents file instead of the .source. file conventions.

mdsnippets -r true

mdsnippets --read-only true

Defining Snippets

Any code wrapped in a convention based comment will be picked up. The comment needs to start with begin-snippet: which is followed by the key. The snippet is then terminated by end-snippet.

// begin-snippet: MySnippetName
My Snippet Code
// end-snippet

Named C# regions will also be picked up, with the name of the region used as the key.

To stop regions collapsing in Visual Studio disable 'enter outlining mode when files open'. See Visual Studio outlining.

UrlsAsSnippets

Urls to files to be included as snippets. Space separated for multiple values.

Each url will be accessible using the file name as a key. Any snippets within the files will be extracted and accessible as individual keyed snippets.

mdsnippets --urls-as-snippets "https://github.com/SimonCropp/MarkdownSnippets/snippet.cs"

mdsnippets -u "https://github.com/SimonCropp/MarkdownSnippets/snippet.cs"

Using Snippets

The keyed snippets can be used in any documentation .md file by adding the text snippet: KEY.

Then snippets with that key.

For example

Some blurb about the below snippet
snippet: MySnippetName

The resulting markdown will be:

<!-- snippet: MySnippetName -->
Some blurb about the below snippet
<a id='snippet-MySnippetName'></a>
```
My Snippet Code
```
<sup><a href='/relativeUrlToFile#L1-L11' title='Snippet source file'>snippet source</a> | <a href='#snippet-MySnippetName' title='Start of snippet'>anchor</a></sup>
<!-- endSnippet -->

Notes:

The vertical bar ( | ) is used to separate adjacent links as per web accessibility recommendations: https://webaim.org/techniques/hypertext/hypertext_links#groups
H33: Supplementing link text with the title attribute

Including a snippet from the web

Snippets that start with http will be downloaded and the contents rendered. For example:

snippet: https://raw.githubusercontent.com/SimonCropp/MarkdownSnippets/master/license.txt

Will render:

<!-- snippet: https://raw.githubusercontent.com/SimonCropp/MarkdownSnippets/master/license.txt -->
<a id='snippet-https://raw.githubusercontent.com/SimonCropp/MarkdownSnippets/master/license.txt'></a>
```txt
The MIT License (MIT)
...
```
<sup><a href='#snippet-https://raw.githubusercontent.com/SimonCropp/MarkdownSnippets/master/license.txt' title='Snippet source file'>anchor</a></sup>
<!-- endSnippet -->

Files are downloaded to %temp%MarkdownSnippets with a maximum of 100 files kept.

Including a full file

If no snippet is found matching the defined name. The target directory will be searched for a file matching that name. For example:

snippet: license.txt

Will render:

<!-- snippet: license.txt -->
<a id='snippet-license.txt'></a>
```txt
The MIT License (MIT)
...
```
<sup><a href='#snippet-license.txt' title='Start of snippet'>anchor</a></sup>
<!-- endSnippet -->

Including a partial file

If no snippet is found matching the defined name. The target directory will be searched for a file matching that name. Using a syntax of #L10-20 you can only include lines 10 to 20 from that file. For example:

<!-- snippet: license.txt#L1-3 -->
<a id='snippet-license.txt#L1-3'></a>
```txt
The MIT License (MIT)
...
```
<sup><a href='#snippet-license.txt' title='Start of snippet'>anchor</a></sup>
<!-- endSnippet -->

Including a C# Method

If no snippet is found matching the defined name. The target directory will be searched for a file matching that name. Using a syntax of #M-MethodName you can reference a specific method. For example:

<!-- snippet: src\ConfigReader\LogBuilder.cs#M-GetHeader -->
<a id='src\ConfigReader\LogBuilder.cs#M-GetHeader'></a>
```cs
...
```
<sup><a href='#src\ConfigReader\LogBuilder.cs' title='Start of snippet'>anchor</a></sup>
<!-- endSnippet -->

LinkFormat

Defines the format of snippet source links that appear under each snippet.

Command line

mdsnippets --link-format Bitbucket

mdsnippets -l Bitbucket

Values

namespace MarkdownSnippets;

public enum LinkFormat
{
    GitHub,
    Tfs,
    Bitbucket,
    GitLab,
    DevOps,
    None
}

^{snippet source | anchor}

Link format None will omit the source link but still keep the snippet anchor.

OmitSnippetLinks

The links below a snippet can be omitted.

Command line

mdsnippets --omit-snippet-links true

Config file

{
  "OmitSnippetLinks": true
}

How links are constructed

switch (linkFormat)
{
    case LinkFormat.GitHub:
        Polyfill.Append(builder, $"{path}#L{snippet.StartLine}-L{snippet.EndLine}");
        return;
    case LinkFormat.Tfs:
        Polyfill.Append(builder, $"{path}&line={snippet.StartLine}&lineEnd={snippet.EndLine}");
        return;
    case LinkFormat.Bitbucket:
        Polyfill.Append(builder, $"{path}#lines={snippet.StartLine}:{snippet.EndLine}");
        return;
    case LinkFormat.GitLab:
        Polyfill.Append(builder, $"{path}#L{snippet.StartLine}-{snippet.EndLine}");
        return;
    case LinkFormat.DevOps:
        Polyfill.Append(builder, $"?path={path}&line={snippet.StartLine}&lineEnd={snippet.EndLine}&lineStartColumn=1&lineEndColumn=999");
        return;
    case LinkFormat.None:
        throw new($"Unknown LinkFormat: {linkFormat}");
}

^{snippet source | anchor}

UrlPrefix

UrlPrefix allows a string to be defined that will prefix all snippet links. This is helpful when the markdown file are being hosted on a site that is not co-located with the source code files. It can be defined in the config file, the MsBuild task, and the dotnet tool.

Command line

mdsnippets --url-prefix "TheUrlPrefix"

Config file

{
  "UrlPrefix": "TheUrlPrefix"
}

Add to Windows Explorer

Use src/context-menu.reg to add MarkdownSnippets to the Windows Explorer context menu.

Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\Directory\Shell]
@="none"
[HKEY_CLASSES_ROOT\Directory\shell\mdsnippets]
"MUIVerb"="run mdsnippets"
"Position"="bottom"
[HKEY_CLASSES_ROOT\Directory\Background\shell\mdsnippets]
"MUIVerb"="run mdsnippets"
"Position"="bottom"
[HKEY_CLASSES_ROOT\Directory\shell\mdsnippets\command]
@="cmd.exe /c mdsnippets \"%V\""
[HKEY_CLASSES_ROOT\Directory\Background\shell\mdsnippets\command]
@="cmd.exe /c mdsnippets \"%V\""