Web Hooks Google Tech Talk

WEB HOOKS and the Programmable World of Tomorrow Jeff Lindsay three years after coining web hooks, people are starting to get excited about them. i’m going to share what they are, why they’re signiﬁcant, and what’s going on in the growing web hooks ecosystem

WEB HOOKS and the Programmable World of Tomorrow Jeff Lindsay i’ve given a version of this talk before, but this time i’d like to try and focus on this “programmable” idea that helped inspire web hooks.

WARNING: Emergent dynamics described ahead. was a guy really excited hearing about web hooks, but was disappointed to see what they are. i’m describing a game changer based on a mechanism that takes one line of code to describe. seems so simple, people assume you can only do simple things. quite the contrary...

go. simple mechanisms can create rich dynamics. easily teach somebody the rules, doesn’t mean they see the implications of those rules. i want to share the implications of this simple mechanism.

in 1997, jon udell talks about websites as data sources that can be reused and remixed today that idea isn’t very novel

“a new programming paradigm that takes the whole Internet as its platform” he envisions the Internet as a programming paradigm

The Programmable Web “The Web as Platform” it starts to manifest as the programmable web and talk of “the web as a platform”

The Programmable Web APIs and Mashups john musser here starts to track apis and mashups in 2005. there are now over 1k apis and increasingly more. apis and mashups became the foundation of the programmable web...

Pro g ramm at ic The Programmable Web APIs and Mashups but are they? after thinking about web hooks and what they can give us, i realized apis and mashups don’t make a programmable web. they make a programmatic web

Pro g ramm at ic The Programmable Web Twitter API lets you use Twitter programmatically. It does not let you program Twitter to do more. they let you use web apps programmatically. they don’t let you program them to do more, whereas web hooks can. so i like to argue that web hooks will bring about the *real* programmable web.

Web Service interwebz User so let’s get speciﬁc. here’s an example scenario showing the use of web hooks.

Web Service Hi, I’m Twickr, a new web service. interwebz User

“Twickr” Cool. Sign me up. interwebz User

“Twickr” Okay, you’re all set. Now listen... interwebz User

“Twickr” I might ﬁnd myself with some data you might be interested in. interwebz User

“Twickr” Alight, hold on a sec... interwebz User

“Twickr” interwebz User hack hackety hack

“Twickr” Could you just post it here when you have any? http://tinyurl.com/6pln4u interwebz User

“Twickr” ...sure, why not. Hmm, what is that URL? interwebz User

“Twickr” It’s a tiny handler I put up on App Engine. interwebz User

“Twickr” What does it do? interwebz User

“Twickr” It doesn’t matter to you. Whatever I want... interwebz User web hooks are just user-deﬁned http callbacks

Web Service EXTENSIBLE interwebz EMPOWERED User but do you see what they did? they made the web service extensible and empowered the user.

a friend of mine got me to explain web hooks to her. not a programmer, but has iphone. she compared it to jailbreaking the iphone: letting users do what they want, customize, add apps, etc having web hooks is like jailbreaking your web apps. opens functional extensibility.

a pseudo code example of what the heart of implementing web hooks looks like. SIMPLE: make an HTTP request to a user-speciﬁed URL on major events

paypal represents on the oldest web hook implementors

their instant payment notiﬁcation is a web hook

“When a customer pays you, PayPal posts a notiﬁcation to your server at a URL you specify.” its framed as a notiﬁcation, but that doesn’t properly imply the usage its intended for: integration.

started thinking about this in 2006. everything ﬂashed before my eyes and was very confused why it wasn’t used more. felt like i was taking crazy pills. today i know why...

compare to REST.

both have been around longer. rest is simpler.. in fact, it’s almost described as “using HTTP properly” but not until it got a name could it be used in discourse to make it popular

REST Hooks rest apis and web hooks are two sides of the same coin they complement each other in ways i’ll get to later but i just want to give this pattern a name, and start associating some ideas with it

Push Pipes Plugins talk is split into three sections ways to look at the use of web hooks icons will hopefully make more sense as i talk about them

Push let’s get started with push people are starting to talk about push and pubsub on the web... although its not the ﬁrst time

1998 (predating rss) microsoft submitted an internet draft to extend http to provide a basic pubsub framework called GENA

it had your standard pubsub terms

and added 4 new methods to http.

it expired a year later in 1999 and the group behind it seemed to disappear. however...

Sneaky! the methods and protocol ended up in the webdav implemented for exchange

but then in 2000, rss 0.92 was released. ﬁve years later it gets an icon and widespread adoption. it started with blog feeds, then comment feeds...

then soon exploded into twitter feeds, photo feeds, activity feeds, event feeds, bookmark feeds even feeds of feeds

it makes you think of feeds like in the telecom world

data coming directly to you

but we know that’s not how it works

? instead we have to go request the data

then it gives it to us. and we do this over and over. are we there yet? are we there yet?

? feeds made sense in a world where feed readers ran on desktops that couldn’t be pushed to over http

? of course, now we have other web applications consuming feeds and it doesn’t make sense. even most of our feed readers have become web applications

SUP is a recent incremental solution to increase the eficiency of consuming large amounts of feeds. however, its based on polling and is essentially yet another feed, so i couldn’t help...

SUP DAWG, WE HEARD YOU LIKE FEEDS SO WE MADE YOU A FEED OF OUR FEEDS

evan and kellan gave a great talk a while back about this push issue, and their proposed solution: xmpp i have a condensed version of this talk. the slides speak for themselves

(aka XMPP) they have a great point. polling sucks, and xmpp is a pretty good solution for data streams

but it’s kind of heavy weight. it does a lot and makes a decently complex little system. luckily it’s not *that* hard to use with today’s library support

evan and kellan did point out there are extremes when it comes to data streams. most data streams will probably fall somewhere in between, but i do think xmpp is suited for the fast and furious end

joshua schachter of delicious responded to this talk in a blog post. he basically suggests web hooks as an alternative

“One solution that occurred to me at the time was to build a simple callback system over HTTP. This would fall comfortably between full polling and full persistent publish/subscribe.” he says they fall comfortably between polling and xmpp. i agree, and think they can cover most use-cases

others seem to agree.... this is a standard for discovering and subscribing to content changes. they let you use web hooks OR xmpp, which is nice. good idea, but (like GENA) standard specs alone don’t get very far

gnip is a service that some may have heard of (but don’t understand)

Polling their main goal is to stop polling as a service in the middle.

Source Destination Protocol + Mechanism Protocol + Mechanism Format Format Web Hooks Web Hooks RSS RSS XMPP XMPP Atom Atom XML XML REST REST Publisher Consumer they’re basically an adaptor for data streams, letting you pick your own protocol and mechanism, no matter what the feed publisher is providing.

Source Destination Protocol + Mechanism Protocol + Mechanism Format Format Web Hooks Web Hooks RSS RSS XMPP XMPP Atom Atom XML XML REST REST Publisher Consumer however, they recently dropped support to consume via xmpp, making web hooks their primary push mechanism for consuming data streams.

Source Protocol + Mechanism Protocol + Mechanism Format Format Web Hooks Web Hooks RSS RSS XMPP XMPP Atom Atom XML XML REST REST Publisher Consumer as an example, if i wanted to get digg updates via web hooks, gnip will poll digg for me and invoke my callback with the content as new updates come in.

Source Protocol + Mechanism Protocol + Mechanism Format Format Web Hooks Web Hooks RSS RSS XMPP XMPP Atom Atom XML XML REST REST Publisher Consumer alternatively, i could even poll gnip for digg updates. although seemingly redundant, it helps ease the load on digg and allows gnip to provide ﬁltering functionality.

Protocol + Mechanism Protocol + Mechanism Format Format Web Hooks Web Hooks RSS RSS XMPP XMPP Atom Atom XML XML REST REST Publisher Consumer but another example might be if twitter provides an xmpp stream, but i already have a polling setup... gnip would let me poll instead of integrate xmpp.

microformats in promoting web hooks, i sort of look up to the way microformats work in values and process. very ground up, grassroots... take existing popular use-patterns and make it a convention. microformats can be viewed as an alternative xml+rdf

xml+rdf vs microformats “Here's a new language we want you to learn, and now you need to output these additional ﬁles on your server. It's a hassle. (Microformats) lower the barrier to entry.” tantek is a big microformats evangelist. he says.... so i told him about web hooks. “what are they?” “push over http” “how are they di than xmpp?” “they’re a lightweight alternative” lower the barrier to entry...

xmpp vs web hooks “Good. XMPP needs a competitor.” he says... this was encouraging. i mean, when tantek talks, you listen... if for no other reason than

he gets the chicks

unfortunately, xmpp has many features and proposals to do pubsub that web hooks doesn’t.... after all, it’s just a creative use of http requests, not a messaging protocol. so in order to do pubsub with web hooks, you need more to be implemented. well, brad ﬁtzpatrick and brett slatkin are working on that.

Push is good. so the moral here is that push is good and there’s ﬁnally a demand for it. we have some good solutions waiting adoption...

XMPP is ideal when needed, but Web Hooks generally do the job. as far as xmpp vs web hooks, i think they both have their place. web hooks are easier, so you might as well default to web hooks unless you really need xmpp.

But push is not the point. however, as i framed this talk, it’s really not about push. it’s a nice way to get the social media kids into bed with web hooks, but hooks are really about more than pubsub and notiﬁcations. otherwise i would have called them web notiﬁcations or something...

Pipes instead of push, i was more drawn by the pipes metaphor. i wanted to integrate and orchestrate the web applications i use, conceptually similar to unix pipelining.

so i thought about it. pipes were a really amazing feature that let you get more out of your commands by letting you chain them together. it sort of let you program without programming, combining commands in ways that weren’t necessarily intended by the author.

Input Output Program all from a bit of infrastructure involving input and output

STDIN STDOUT Program STDERR stdin, stdout were available to reroute wherever the user wanted most common use was chaining commands together: piping

xargs wget echo mail grep wc cat so you had all these simple little programs, that might not even be useful alone

cat xargs wget echo mail grep wc string them together...

cat grep xargs wget echo mail wc

cat grep mail xargs wget echo wc and you have something more useful than the sum of the parts

Write programs that do one thing and do it well. Write programs to work together. Write programs that handle text streams, because that is a universal interface. this helped put forth the unix philosophy and encouraged building these small composable commands

STDIN Program but it doesn’t work without the output. it just breaks.

API Web App unfortunately that’s how the web is today. we can talk to web apps, but they really can’t talk to us. or anything else really.

API Hooks Web App it’s not that they can’t, they just don’t. we just need to start putting hooks in so they can. those roles are best played by mechanisms that use the protocol the web is built on: http

backhoe

+ front-loader + excavator

cat grep mail Basecamp so we want to combine web applications like we can CLI programs. get more than the sum of the parts. web hooks open up this possibility, but need like APIs, need to be implemented

Basecamp imagine basecamp with a bunch of hooks for events

Basecamp Project ﬁnished Todo completed Milestone created Contact added File uploaded

Basecamp My handler http://example.com/handler users can write handlers that are just web scripts. they have a url, and thats what you give basecamp

Basecamp My handler http://example.com/handler it’s code. it can do anything from there. integrate with other services, make a phone call, order pizza, whatever

Todos Basecamp for example, all these apps share data about todos. they each have respective specialized talents, but all work with todos. by putting hooks on todo CRUD, you can use their apis to keep them synced pretty well. magically. real-time.

Service integration web hooks enable service integration

Composability adding composability to web apps

Code as glue based on the idea that web urls can run code. and code can do anything.

when i ﬁrst thought about this, cheap PHP hosting was all over, but it could be even simpler. there are paste bins like this one. made to share formatted code with people over IRC or email

put in some code you want to share or ask a question about

http://pastie.org/84826 hit save and you get a URL you can share when you ask “where’s the data stored?”

i’m thinking of the same thing, but that you write handlers with

http://pastie.org/run/24576 and saving doesn’t just give a url to view, but to run. pass that url into an app with web hooks

Basecamp Project finished http://pastie.org/run/24576 for example, basecamp. now when you ﬁnish a project, everybody meets for shots in the break room.

fortunately, we have this. it’s called appjet by ex googlers.

just hit a button, write code, hit save, share the url. it’s javascript

obviously app engine, although it’s a little more involved than appjet for quick handlers. but it is an option for python. and there are ruby/rails hosts like heroku

one thing i’ve been working on is an extension to play with ways end-users might interact with web hooks

Hey, there’s an event hook here! by detecting some markup in a page, it discovers hooks. like say for new photos from contacts. you want to do something when that happens, click it

Save and write some code. hit save, it posts to AppJet (or wherever), registers the handler (assuming a standard protocol), and done. all inline. go back and change the code.

Real world examples but these are all mockups and what-ifs... there is a world of web hooks already evolving...

i started by exposing svn hooks as web hooks in devjavu

i talked about web hooks enough using pbwiki as an example, their mysterious cto decided to implement them

and apparently really liked what he found

went all out on hooked events. not sure if it’s made it to production, but really cool

“Building projects with web hooks in mind lets me keep the core Lighthouse source focused, while external services live in their own libraries.” --Rick Olson the idea silently spread to rails guys. rick olson used them in lighthouse

“We implemented web hooks a while ago and people have been building all sorts of unexpected stuff on top of it.” --Tobias Lütke tobias used them in shopify. i’m told he’s revamping their api to have more hooks. they were one of the earliest adopters and recently had their 1 yr anniversary using web hooks

google code recently caught up other code hosts by providing a post commit hook. it was very well done, as you’d expect from google and in particular shows that authentication can be done with hmac signatures

github was one of the ﬁrst majorly popular site to use and promote web hooks.

they’ve been doing really well with their post-receive hook. users have used it to integrate with mailing lists, chat, other project management tools, continuous integration, etc

they were so successful with the adhoc integration, they formalized it. but in the best way! using their existing web hook infrastructure. they just have modules running in a separate but local web service.

in fact, that lets them open source it. letting people fork, write new handlers, and push back. this is probably going to be the standard model of service integration.

and a great example of services integrated with github, besides lighthouse, is runcoderun. they run your regression tests for you. continuous integration in the sky. love it. they sign you up automatically if you put their hook in github.

and of course i mentioned paypal. but i should mention, web hooks make so much sense for paypal... they’re not so much about pushing content, but INTEGRATING. that’s what web hooks are great for, even though they can be used for content push.

jott is another example of a web hook implementer that doesn’t know it. they parse voice over the phone and do stu with it, like post to twitter, etc

they do it with “Links”... which are just hooks. they post to a script that does something with the parsed text. really cool for todos.

Jott reads back the The message is Message is sent via User receives User jotts to response and sends converted HTTP Post to a information back a Jott Link it via SMS & SMTP into text web page here’s their diagram. totally web hooks.

it become obvious making adaptor services would not only be useful in speciﬁc cases, but in general, it makes sense to have services that will turn other protocols into inputs to the web hook ecosystem. the ﬁrst was email... i built mailhook...

GAE community made one because GAE doesn’t have a way to accept email (but will soon). web hooks were the obvious solution.

rick olson has an open source non-hosted ruby version that will do xmpp. he uses it for lighthouse.

but smtp2web is interesting because it was made because of the limitations of GAE...

in fact a lot of people made these kinds of “micro webservices” to do simple things GAE didn’t do. it was the ﬁrst glimpse at small, focused services that are like the equivalent of grep, cat, wordcount, etc in the command line piping ecosystem.

then there’s martyn and andy. two guys in the uk that love web hooks. they built this thing called spaghetti junction at a hackday. it involved into...

switchub. i REALLY love this. i knew this sort of thing would emerge, but i didn’t think it would happen until web hooks were more popular. kind of like the pastinbin code runner, they let you create hook inputs with urls to put in apps that you can route to various output handlers: email, irc, etc

my example switchboard. this kind of feels like gnip, only more focused and more about web hooks. so i like it lots.

opening handlers up like github. anybody can write handlers soon. working with them a little to make it real awesome.

switchub would beneﬁt from builtin inputs from various other protocols like email, rss, etc... but instead of having them builtin, they can work with other services to support those kinds of inputs. for example, rssfwd could easily be modiﬁed to provide a web hook for rss

switchub is a lot like how i visualized a way for regular users to orchestrate web apps. was inspired by reason: virtual rack mounts

ﬂip it around and wire them together however you like. totally cool.

Plugins there’s one more thing i want to talk about.

web was a bunch of pages linked together.

but people kept wanting to access other things through the web (like me today)

so they developed cgi

tangent: this is a neat ﬁnd. was on reddit. andreessen proposing IMG tag. people fought it, said it needed to be more generalized. he just put it on mosaic and that was that

so these pages... today... because of cgi

are actually the result

of these higher order nodes... the code... the apps. this is most of the web today. neat how that evolved

so you have these applications

and the dierence you might think is backend and frontend. but there is a subtly dierent way to think about it

Application Pages logic and content. the read-write web gave us user contributed content... i want user contributed (democratized) logic.

Function Content logic and content. the read-write web gave us user contributed content... i want user contributed (democratized) logic.

Integrate Function Content not just integrating and composing apps

Extend Integrate Function Content but extending apps...

almost called this section Platforms. platforms are really cool. we all love them. i LOVE them, so fb platform was really cool. asked a friend how it worked. he said “web hooks”

sure enough, this looks like web hooks to me. as long as it’s http, calling out... but then using the results in their app? thats dierent...

in fact a few people have used web hooks for plugins. dabble is a great example.

they do online databased for people that use excel as a database.

their plugin API is great. it uses web hooks!

“Dabble plugins allow Dabble applications to create new, derived ﬁelds by calling out to external HTTP-accessible applications. This solves the problem of safely enabling extension of a centrally-located hosted application, in that, while you’re writing code to extend and enhance the behavior of a Dabble application, your code never actually runs inside Dabble.” [General] Name = Amazon Sales Rank [Sales Rank by ISBN] URL = http://chadfowler.com/dabble/amazon_sales_rank.cgi Input = Text Output = Number only they have an extra layer for meta data. but that’s a cool pattern.

“If you’ve used a UNIX-based operating system, you’re probably familiar with the notion of pipes. The output of one program is piped into the input of another, creating a ﬁlter chain. This is conceptually the same as the way Dabble’s plugin IO works. Nice and simple.” of course, they compare it to pipes. the simplicity. the natural ﬁt of it.

of course, i think they should have web hooks for all their standard CRUD events... this way their database apps can integrate (like PayPal) with the rest of your workﬂow

in fact, all these “app platforms” like coghead and salesforce should have web hooks. that would make them more useful, less silo’d o into just processing data in their world

IMiﬁed uses web hooks. sells the tech too: “allows anyone with basic web programming skills to quickly and easily create ...”

General Systems Theory close by dropping some GST on you

General Systems Theory central tenet is value is not in the elements or parts of a system

General Systems Theory the real value is in the interactions, how they work together. this creates the emergent phenomenon of a system, and deﬁnes its behavior

Degrees of freedom increase the ways to work together, the means of combination, increases the DoF

Increase possibility space uncover new opportunities in business, tools, and empowerment

“a new programming paradigm that takes the whole Internet as its platform” this vision for a programming paradigm that IS the internet/web is very compelling... but we’re not there yet.

The Programmable Web APIs and Hooks the real programmable web will require

http://flickr.com/photos/nikonfans/439432049/ http://flickr.com/photos/omegaman/477866054/ http://flickr.com/photos/aquan/2780542698/ http://flickr.com/photos/lucky_13/191038503/ http://flickr.com/photos/narwhal85/1290912011/ http://flickr.com/photos/thomashawk/521532598/ http://flickr.com/photos/bendodson/2601002535/ http://flickr.com/photos/ntr23/218966763/ http://flickr.com/photos/shrimphead/2259353414/ http://flickr.com/photos/raphaelmuli/2913907316/ http://flickr.com/photos/x180/467764284/ http://flickr.com/photos/x180/1704475856/ Thanks! webhooks.org

“What is the equivalent of the pipe in the age of the web?” in 2000, just as rss 0.92 was being released, tim oreilly asks... since we had nothing better, we assumed the answer was feeds.

this eventually gave us yahoo pipes. which just didn’t seem to change the game like you would think... perhaps feeds just aren’t the answer. or maybe they are and the problem is using the pipes analogy. it’s deﬁnitely a stretch...

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Web Hooks Google Tech Talk

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