From 2d2a43f200b88627253f2906fbae87cef7c1e8ce Mon Sep 17 00:00:00 2001 From: Franck Cuny Date: Thu, 4 Aug 2016 11:12:37 -0700 Subject: Mass convert all posts from markdown to org. --- ...2010-04-03-more-fun-with-tatsumaki-and-plack.md | 160 --------------------- 1 file changed, 160 deletions(-) delete mode 100644 posts/2010-04-03-more-fun-with-tatsumaki-and-plack.md (limited to 'posts/2010-04-03-more-fun-with-tatsumaki-and-plack.md') diff --git a/posts/2010-04-03-more-fun-with-tatsumaki-and-plack.md b/posts/2010-04-03-more-fun-with-tatsumaki-and-plack.md deleted file mode 100644 index 233ad98..0000000 --- a/posts/2010-04-03-more-fun-with-tatsumaki-and-plack.md +++ /dev/null @@ -1,160 +0,0 @@ -Lately I've been toying a lot with [Plack](http://plackperl.org/) and two Perl web framework: [Tatsumaki](http://search.cpan.org/perldoc?Tatsumaki) and [Dancer](http://search.cpan.org/perldoc?Dancer). I use both of them for different purposes, as their features complete each other. - -## Plack - -If you don't already know what Plack is, you would want to take a look at the following Plack resources: - -* [Plack (redesigned) website](http://plackperl.org) -* [Plack documentation](http://search.cpan.org/perldoc?Plack) -* [Miyagawa's screencast](http://bulknews.typepad.com/blog/2009/11/plack-and-psgi-screencast-and-feedbacks.html) -* [Plack advent calendar](http://advent.plackperl.org/) - -> As [sukria](http://www.sukria.net/) is planning to talk about [Dancer](http://perldancer.org) during the [FPW 2010](http://journeesperl.fr/fpw2010/index.html), I will probably do a talk about Plack. - -After reading some code, I've started to write two middleware: the first one add ETag header to the HTTP response, and the second one provides a way to limit access to your application. - -### Plack::Middleware::ETag - -This middleware is really simple: for each request, an [ETag](http://en.wikipedia.org/wiki/HTTP_ETag) header is added to the response. The ETag value is a sha1 of the response's content. In case the content is a file, it works like apache, using various information from the file: inode, modified time and size. This middleware can be used with [Plack::Middleware::ConditionalGET](http://search.cpan.org/perldoc?Plack::Middleware::ConditionalGET), so the client will have the ETag information for the page, and when he will do a request next time, it will send an "if-modified" header. If the ETag is the same, a 304 response will be send, meaning the content have not been modified. This module is [available on CPAN](http://search.cpan.org/perldoc?Plack::Middleware::ETag). - -Let's see how it works. First, we create a really simple application (we call it app.psgi): - -```perl -#!/usr/bin/env perl -use strict; -use warnings; -use Plack::Builder; - -builder { - enable "Plack::Middleware::ConditionalGET"; - enable "Plack::Middleware::ETag"; - sub { - ['200', ['Content-Type' => 'text/html'], ['Hello world']]; - }; -}; -``` - -Now we can test it: - -```bash -% plackup app.psgi& -% curl -D - http://localhost:5000 -HTTP/1.0 200 OK -Date: Sat, 03 Apr 2010 09:31:43 GMT -Server: HTTP::Server::PSGI -Content-Type: text/html -ETag: 7b502c3a1f48c8609ae212cdfb639dee39673f5e -Content-Length: 11 - -% curl -H "If-None-Match: 7b502c3a1f48c8609ae212cdfb639dee39673f5e" -D - http://localhost:5000 -HTTP/1.0 304 Not Modified -Date: Sat, 03 Apr 2010 09:31:45 GMT -Server: HTTP::Server::PSGI -ETag: 7b502c3a1f48c8609ae212cdfb639dee39673f5e -``` - -### Plack::Middleware::Throttle - -[With this middleware](http://git.lumberjaph.net/p5-plack-middleware-throttle.git/), you can control how many times you want to provide an access to your application. This module is not yet on CPAN, has I want to add some features, but you can get the code from git. There is four methods to control access: - -* Plack::Middleware::Throttle::Hourly: how many times in one hour someone can access the application -* P::M::T::Daily: the same, but for a day -* P::M::T::Interval: which interval the client must wait between two query -* by combining the three previous methods - -To store sessions informations, you can use any cache backend that provides `get`, `set` and `incr` methods. By default, if no backend is provided, it will store informations in a hash. You can easily modify the defaults throttling strategies by subclassing all the classes. - -Let's write another application to test it: - -```perl -#!/usr/bin/env perl -use strict; -use warnings; -use Plack::Builder; - -builder { - enable "Plack::Middleware::Throttle::Hourly", max => 2; - sub { - ['200', ['Content-Type' => 'text/html'], ['Hello world']]; - }; -}; -``` - -then test - -```bash -% curl -D - http://localhost:5000/ -HTTP/1.0 200 OK -Date: Sat, 03 Apr 2010 09:57:40 GMT -Server: HTTP::Server::PSGI -Content-Type: text/html -X-RateLimit-Limit: 2 -X-RateLimit-Remaining: 1 -X-RateLimit-Reset: 140 -Content-Length: 11 - -Hello world - -% curl -D - http://localhost:5000/ -HTTP/1.0 200 OK -Date: Sat, 03 Apr 2010 09:57:40 GMT -Server: HTTP::Server::PSGI -Content-Type: text/html -X-RateLimit-Limit: 2 -X-RateLimit-Remaining: 0 -X-RateLimit-Reset: 140 -Content-Length: 11 - -Hello world - -% curl -D - http://localhost:5000/ -HTTP/1.0 503 Service Unavailable -Date: Sat, 03 Apr 2010 09:57:41 GMT -Server: HTTP::Server::PSGI -Content-Type: text/plain -X-RateLimit-Reset: 139 -Content-Length: 15 - -Over rate limit -``` - -Some HTTP headers are added to the response : - -* **X-RateLimit-Limit**: how many request can be done -* **X-RateLimit-Remaining**: how many requests are available -* **X-RateLimit-Reset**: when will the counter be reseted (in seconds) - -This middleware could be a very good companion to the [Dancer REST stuff](http://www.sukria.net/fr/archives/2010/03/19/let-the-dancer-rest/) [added recently](/easily-create-rest-interface-with-the-dancer-1.170/). - -## another Tatsumaki application with Plack middlewares - -To demonstrate the use of this two middleware, [I wrote a small application](http://git.lumberjaph.net/p5-feeddiscovery.git/) with Tatsumaki. This application fetch a page, parse it to find all the feeds declared, and return a JSON with the result. - -```bash -% GET http://feeddiscover.tirnan0g.org/?url=http://lumberjaph.net/blog/ -``` - -will return - -```javascript -% [{"href":"http://lumberjaph.net/blog/index.php/feed/","type":"application/rss+xml","title":"i'm a lumberjaph RSS Feed"}] -``` - -This application is composed of one handler, that handle only **GET** request. The request will fetch the url given in the **url** parameter, scrap the content to find the links to feeds, and cache the result with Redis. The response is a JSON string with the informations. - -The interesting part is the app.psgi file: - -```perl -my $app = Tatsumaki::Application->new(['/' => 'FeedDiscovery::Handler'],); - -builder { - enable "Plack::Middleware::ConditionalGET"; - enable "Plack::Middleware::ETag"; - enable "Plack::Middleware::Throttle::Hourly", - backend => Redis->new(server => '127.0.0.1:6379',), - max => 100; - $app; -}; -``` - -The application itself is really simple: for a given url, the Tatsumaki::HTTPClient fetch an url, I use [Web::Scraper](http://search.cpan.org/perldoc?Web::Scraper) to find the **link rel="alternate"** from the page, if something is found, it's stored in Redis, then a JSON string is returned to the client. -- cgit v1.2.3