jekyll-seo-tag/README.md

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# Jekyll SEO Tag
A Jekyll plugin to add metadata tags for search engines and social networks to better index and display your site's content.
[![Gem Version](https://badge.fury.io/rb/jekyll-seo-tag.svg)](https://badge.fury.io/rb/jekyll-seo-tag) [![Build Status](https://travis-ci.org/jekyll/jekyll-seo-tag.svg)](https://travis-ci.org/jekyll/jekyll-seo-tag)
## What it does
Jekyll SEO Tag adds the following meta tags to your site:
* Pages title (with site title appended when available)
* Page description
* Canonical URL
* Next and previous URLs on paginated pages
* [JSON-LD Site and post metadata](https://developers.google.com/structured-data/) for richer indexing
* [Open Graph](http://ogp.me/) title, description, site title, and URL (for Facebook, LinkedIn, etc.)
* [Twitter Summary Card](https://dev.twitter.com/cards/overview) metadata
While you could theoretically add the necessary metadata tags yourself, Jekyll SEO Tag provides a battle-tested template of crowdsourced best-practices.
## What it doesn't do
Jekyll SEO tag is designed to output machine-readable metadata for search engines and social networks to index and display. If you're looking for something to analyze your Jekyll site's structure and content (e.g., more traditional SEO optimization), take a look at [The Jekyll SEO Gem](https://github.com/pmarsceill/jekyll-seo-gem).
Jekyll SEO tag isn't designed to accommodate every possible use case. It should work for most site out of the box and without a laundry list of configuration options that serve only to confuse most users.
## Installation
1. Add the following to your site's `Gemfile`:
```ruby
gem 'jekyll-seo-tag'
```
2. Add the following to your site's `_config.yml`:
```yml
gems:
- jekyll-seo-tag
```
3. Add the following right before `</head>` in your site's template(s):
```liquid
{% seo %}
```
## Usage
The SEO tag will respect any of the following if included in your site's `_config.yml` (and simply not include them if they're not defined):
* `title` - Your site's title (e.g., Ben's awesome site, The GitHub Blog, etc.)
* `description` - A short description (e.g., A blog dedicated to reviewing cat gifs)
* `url` - The full URL to your site. Note: `site.github.url` will be used by default.
* `author` - global author information (see below)
* `twitter:username` - The site's Twitter handle. You'll want to describe it like so:
```yml
twitter:
username: benbalter
```
* `facebook` - The following properties are available:
* `facebook:app_id` - a Facebook app ID for Facebook insights
* `facebook:publisher` - a Facebook page URL or ID of the publishing entity
* `facebook:admins` - a Facebook user ID for domain insights linked to a personal account
You'll want to describe one or more like so:
```yml
facebook:
app_id: 1234
publisher: 1234
admins: 1234
```
* `logo` - URL to a site-wide logo (e.g., `/assets/your-company-logo.png`)
* `social` - For [specifying social profiles](https://developers.google.com/structured-data/customize/social-profiles). The following properties are available:
* `name` - If the user or organization name differs from the site's name
* `links` - An array of links to social media profiles.
```yml
social:
name: Ben Balter
links:
- https://twitter.com/BenBalter
- https://www.facebook.com/ben.balter
- https://www.linkedin.com/in/BenBalter
- https://plus.google.com/+BenBalter
- https://github.com/benbalter
- https://keybase.io/benbalter
```
* `google_site_verification` for verifying ownership via Google webmaster tools
* Alternatively, verify ownership with several services at once using the following format:
```yml
webmaster_verifications:
google: 1234
bing: 1234
alexa: 1234
yandex: 1234
```
The SEO tag will respect the following YAML front matter if included in a post, page, or document:
* `title` - The title of the post, page, or document
* `description` - A short description of the page's content
* `image` - URL to an image associated with the post, page, or document (e.g., `/assets/page-pic.jpg`)
* `author` - Page-, post-, or document-specific author information (see below)
## Advanced usage
Jekyll SEO Tag is designed to implement SEO best practices by default and to be the right fit for most sites right out of the box. If for some reason, you need more control over the output, read on:
### Disabling `<title>` output
If for some reason, you don't want the plugin to output `<title>` tags on each page, simply invoke the plugin within your template like so:
```
{% seo title=false %}
```
### Author information
Author information is used to propagate the `creator` field of Twitter summary cards. This should be an author-specific, not site-wide Twitter handle (the site-wide username be stored as `site.twitter.username`).
*TL;DR: In most cases, put `author: [your Twitter handle]` in the document's front matter, for sites with multiple authors. If you need something more complicated, read on.*
There are several ways to convey this author-specific information. Author information is found in the following order of priority:
1. An `author` object, in the documents's front matter, e.g.:
```yml
author:
twitter: benbalter
```
2. An `author` object, in the site's `_config.yml`, e.g.:
```yml
author:
twitter: benbalter
```
3. `site.data.authors[author]`, if an author is specified in the document's front matter, and a corresponding key exists in `site.data.authors`. E.g., you have the following in the document's front matter:
```yml
author: benbalter
```
And you have the following in `_data/authors.yml`:
```yml
benbalter:
picture: /img/benbalter.png
twitter: jekyllrb
potus:
picture: /img/potus.png
twitter: whitehouse
```
In the above example, the author `benbalter`'s Twitter handle will be resolved to `@jekyllrb`. This allows you to centralize author information in a single `_data/authors` file for site with many authors that require more than just the author's username.
*Pro-tip: If `authors` is present in the document's front matter as an array (and `author` is not), the plugin will use the first author listed, as Twitter supports only one author.*
4. An author in the document's front matter (the simplest way), e.g.:
```yml
author: benbalter
```
5. An author in the site's `_config.yml`, e.g.:
```yml
author: benbalter
```
### Customizing JSON-LD output
The following options can be set for any particular page. While the default options are meant to serve most users in the most common circumstances, there may be situations where more precise control is necessary.
* `seo`
* `name` - If the name of the thing that the page represents is different from the page title. (i.e.: "Frank's Café" vs "Welcome to Frank's Café")
* `type` - The type of things that the page represents. This must be a [Schema.org type](http://schema.org/docs/schemas.html), and will probably usually be something like [`BlogPosting`](http://schema.org/BlogPosting), [`NewsArticle`](http://schema.org/NewsArticle), [`Person`](http://schema.org/Person), [`Organization`](http://schema.org/Organization), etc.
* `links` - An array of other URLs that represent the same thing that this page represents. For instance, Jane's bio page might include links to Jane's GitHub and Twitter profiles.
### Customizing image output
For most users, setting `image: [path-to-image]` on a per-page basis should be enough. If you need more control over how images are represented, the `image` property can also be an object, with the following options:
* `path` - The relative path to the image. Same as `image: [path-to-image]`
* `height` - The height of the Open Graph (`og:image`) image
* `width` - The width of the Open Graph (`og:image`) image
You can use any of the above, optional properties, like so:
```yml
image:
path: /img/twitter.png
height: 100
width: 100
```
### Setting a default image
You can define a default image using [Front Matter default](https://jekyllrb.com/docs/configuration/#front-matter-defaults), to provide a default Twitter Card or OGP image to all of your posts and pages.
Here is a very basic example, that you are encouraged to adapt to your needs:
```yml
defaults:
- scope:
path: ""
values:
image: /assets/images/default-card.png
```
### SmartyPants Titles
Titles will be processed using [Jekyll's `smartify` filter](https://jekyllrb.com/docs/templates/). This will use SmartyPants to translate plain ASCII punctuation into "smart" typographic punctuation. This will not render or strip any Markdown you may be using in a page title.