h1. Add webmention client code to Junco

Access these tags and links:

* #webmention
* #indieweb
* [[IndieWebCamp principles for building the indie Web]]
* http://webmention.org
* http://indiewebcamp.com/webmention
* https://github.com/phpish/webmention 

"The ability for one webpage to let another know the first has linked to the second is a vital indieweb building block.
The key mention technology for the indieweb is: webmention"


http://gist.github.com/adactio/6575229 - "The form I put at the end of every blog post I make so that you can ping my webmention endpoint with your response."

code.<form method="post" action="/webmention.php">
<p>Have you published a response to this?
<label for="webmention-source">Let me know the <abbr title="Uniform Resource Locator">URL</abbr></label>:
</p>
<input type="url" name="source" id="webmention-source">
<input type="hidden" name="target" value="http://adactio.com/journal/6495/">
<input type="submit" value="Ping!">
</form>
code..

Sep 15, 2013 - "Parsing webmentions":http://adactio.com/journal/6495/


h2. Understanding

I'm still trying to understand webmentions and pingbacks. 

I guess that I viewed this more as a remote-commenting function. 

* Blogger A creates a post
* Blogger B would like to "comment" on Blogger A's post, but A does not allow comments.
* Blogger B can create a post that is responding to A, but unless B contacts A through e-mail or some other means, A will be unaware of B's blog response.
* But if Blogger A supported some kind of remote commenting system, and maybe that could be webmention, then Blogger B could create a blog post and include the URL to Blogger A's post.
* at the bottom of Blogger A's post would be Blogger B's blog post response title, which would be a link to Blogger B's reply post.
* Blogger B can only create one blog post response for each blog post by A.

The above would work and display similar to my reply as a blog post function in my Kestrel code that was removed when I started over with the Junco codebase.

Maybe a remote comment procedure would send to the original blog post app:

* reply blog post URL
* reply blog post title
* reply blog post author name/username that links to Blogger B's home page
* reply blog post creation/published date (date sent to Blogger A)
* an optional brief description or intro to the blog post, limited to x-number words or characters (Blogger A's software could set the char or word limit or not display the description at all)

Make it a POST request from Blogger B to Blogger A, and encapsulate the above info in JSON.

Could still be abused by spammers and trolls, unless Blogger A establishes a white list of users permitted to create blog replies. Blogger B would have to seek permission from Blogger A to be on the whitelist.


h2. Webmention Protocol Summary

From http://indiewebcamp.com/webmention

Assuming Aaron's blog supports receiving webmentions, and Barnaby's blog supports sending webmentions:

# User Aaron posts a blog post on his blog
# User Barnaby writes post on his blog that links to Aaron's post.
# After publishing the post (i.e. it has a URL), Barnaby's server notices this link as part of the publishing process
# Barnaby's server does webmention discovery on Aaron's post to find its webmention endpoint (if not found, process stops)
# Barnaby's server sends a webmention to Aaron's post's webmention endpoint with
source set to Barnaby's post's permalink
target set to Aaron's post's permalink.
# Aaron's server receives the webmention
# Aaron's server verifies that target (after following redirects) in the webmention is a valid permalink on Aaron's blog (if not, processing stops)
# Aaron's server verifies that the source (when retrieved, after following redirects) in the webmention contains a hyperlink to the target (if not, processing stops)

Unmentioned but implied (and vaguely mentioned in the pingback spec):

* Aaron's server displays the information about Barnaby's post somewhere on Aaron's post.

#todo
#junco