How to upgrade Meetup.com API to OAuth2 with Guzzle

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• Mon, Jun 17, 2019
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There is no information about Meetup.com API upgrade on their blog, so I'll share the email to give you an idea:

• API Keys will be replaced by OAuth: We will be removing API keys on August 15, 2019 and requiring you to authenticate with OAuth.

• Move to OAuth soon for continued free API access: Until August 15, members will be able to apply for OAuth access free of charge. After August 15, anyone who wants to apply for API access through OAuth will need to have a Meetup Pro account in order to do so.

Documentation vs. Code

This is a simple task, that in the end has simple 15 lines of new code. But documentation turned it into almost 3 hours of work.

It seems like OAuth2 must be something very new, because Guzzle supports only Oauth (1). If the last commit in 2014 can be called "supports".

After a bit of Googling if found kamermans/guzzle-oauth2-subscriber. I tried to copy-paste the code

Choose Your Path

• Do you want to just read copy paste solution? Jump to 5 Steps to Guzzle OAuth2 headline.
• If you want to learn about writing software and documentation, keep on reading.

Fuck-up #1: Put Oldest First

Why would you put the newest content first, right? You know, like on Twitter, Facebook, basically any news, messages...

If you write a code that other people read, you should read The Design of Everyday Things or Don't Make Me Think

So now you can imagine I'm using the latest Guzzle 6 and trying to implement a solution for Guzzle 4 & 5.

Fuck-up #2: Support All Versions

Fuck-Up #1 is a natural consequence of trying to support multiple versions at one branch/tag. Instead of putting all code to one branch, let always the last branch support the latest LTS dependencies.

What does that mean?

Let's look at Symfony repository. Instead of "Symfony" imagine any package that is version. Now there is Symfony 4, so there was version 3, 2, 1 in the past. Like Guzzle 6, 5, 4...

Now you've decided to upgrade and look for CHANGELOG.md (because you haven't heard about Rector yet):

But how do you upgrade from Symfony 3? In the latest branch, there is always context-aware information. Do you need any older version? Switch to branch 3.x or 2.x.

I love this, because it focuses on mainstream, providing minimal needed data, but also allows the same for minorities.

The Symfony docs does the same:

I wrote about this in detail in What can You Learn from Menstruation post.

Fuck-up #3: Provide more solutions

After I figured out the README is not text for programmers but for detectives, I've found the code with middleware I though I was looking for:

<?php

$oauth = new OAuth2Middleware($grant_type);

$stack = HandlerStack::create();
$stack->push($oauth);

$client = new Client([
    'auth'     => 'oauth',
    'handler'  => $stack,
]);

This supposes to work... but instead I got as useless exceptions as "cannot authenticate". After 60 minutes of trying, I went to sleep with frustration.

In the morning I've noticed little note:

Tried it and it worked. WTF? Why there is a broken code first, then "working alternative" second?

This is a common problem with double complexity = exponential bugs. If you translate your website to English and German, it will have more translation bugs than the English-only version. Of course, German might be important to your business, but the alternative code has as little added value as having a website in American English and British English.

How to Write Perfect Documentation?

It's important to know, that I don't try to make this about the specific documentation, but rather about any open-source documentation and how it's written.

If I'd be sending an invoice to my employer, it would look like this:

• 2,5 hours - debugging documentation
• 0,5 hours - implementing OAuth2

How to Lower Those 2,5 hours to 15 minutes?

Let's pause a bit and think - what do we really need, when we use the package for the first time?

• get a code that solves our problem (e.g. use OAuth2 with Guzzle to prevent paying $ for Meetup.com API)
• solve it as fast as possible (e.g. in 30 minutes)
• a code, that we can copy paste and it works (e.g. without looking for missing use statements - I just hate this!)
• feel confident we understand the errors, so we can fix them ourselves (e.g. without StackOverflow, creating and issue on Github)

If we agree on these as our priorities, then all we need is working piece of code.

Be Sure the Code Works without Testing it

How do we know the code is working?

• it's tested
• test passing
• we can see test passing ourselves on Travis CI or Gitlab CI

Instead of having documentation with text (= "weak strings"), the best would be:

• link to the code for Guzzle 6
• link to test case for Guzzle 6
• link to CI passing for a test case for Guzzle 6

That's the perfect documentation, because we can skip the verification and detective part and trust it by validated contract.

Now finally to the solution ↓

5 Steps to Guzzle Oauth2

• Login to Meetup.com
• Create new consumer here - https://secure.meetup.com/meetup_api/oauth_consumers - it's credentials actually
• There you get Oauth key and secret
• Have the latest guzzle + oauth2-subscriber

composer require guzzlehttp/guzzle:^6.3
composer require kamermans/guzzle-oauth2-subscriber

• Use Guzzle with Oauth2

<?php declare(strict_types=1);

require __DIR__ . '/vendor/autoload.php';

use GuzzleHttp\Client;
use kamermans\OAuth2\GrantType\ClientCredentials;
use kamermans\OAuth2\OAuth2Middleware;

// get these here: https://secure.meetup.com/meetup_api/oauth_consumers
$meetupComOauth2Key = '123';
$meetupComOauth2Secret = 'ABC';

// boilerplate code for Oauth2
$oAuth2Client = new Client([
    // URL for access_token request
    'base_uri' => 'https://secure.meetup.com/oauth2/access',
]);

$oAuth2Config = [
    'client_id' => $meetupComOauth2Key,
    'client_secret' => $meetupComOauth2Secret,
];
$clientCredentials = new ClientCredentials($oAuth2Client, $oauthConfig);
$oAuth2Middleware = new OAuth2Middleware($clientCredentials);

// the main code
$client = new Client();
$client->getConfig('handler')->push($oAuth2Middleware);

// call anything
$response = $client->request('GET', '...');
var_dump($response);

But does it still work?

Happy coding!