Writing and using php streams and sockets tek11

 Idea originating in 1950’s  Standard way to get Input and Output  A source or sink of dataDefinitions  C – stdin, stderr, stdout  C++ iostreamWho uses them  Perl IO  Python io  Java  C#

These are the people you can blame for the PHP streams implementation

 We will write code (in pairs) There will be a quiz (with prizes) You get out what you put in – participate!This is really 3 talks in one - Streams Filters Sockets

Abstracting I/O

 Access input and output generically Can write and read linearly May or may not be seekable Comes in chunks of data

 EVERYTHING include/require _once stream functions file system functions many other extensions

Stream Contexts Stream StreamALL IO Filter Wrapper

 Stream › Resource that exhibits a flow or succession of data Wrapper › Tells a stream how to handle specific protocols and encodings Context › A set of parameters and options to tell a stream (or filter) how to behave

 Scheme › The name of the wrapper to be used. file, http, https, ftp, etc. Target › Depends on the wrapper, filesystem uses a string path name, ssh2 uses a PHP resource home/bar/foo.txt file:///home/bar/foo.txt http://www.example.com/foo.txt ftp://user:pass@ftp.example.com/foo.txt php://filter/read=string.toupper|string.rot13/resource =http://www.example.com

 flock wrapper limitations non-existent pointers (infinite loops can and will happen) error handling

 Parameters Options Modify or enhance a stream stream_context_set_param stream_context_set_option stream_context_create

Streams available by default

 file:// http:// ftp:// data:// glob://

 SSL  Phar › https:// › phar:// › ftps://  Zlib › ssl:// › compress.zlib:// › tls:// › zlib:// SSH  Bzip › ssh2.shell:// › compress.bz2:// › ssh2.exec:// › ssh2.tunnel:// › ssh2.sftp:// › ssh2.scp://

 Pipes STDIN, STDOUT, STDERR proc_open popen

 php://stdin php://stdout php://stderr php://output php://input php://filter (5.0.0) php://memory (5.1.0) php://temp (5.1.0)

1. Get a Feed from Flickr - http://www.flickr.com/services/feeds/2. No curl installed, allow_url_fopen is on3. Display however you would like

Grab the feed as xml, pop it through simplexml, loop and display the output to a webpage

Userland Filters and Streams

 There are no interfaces Implement as though there were an interface Seekable is optional Flushable is optional Directory support is optional

 fopen  file_get_contentsInformation  Return true or false  $this->context will have any context metadataCode

 fread  fgets  file_get_contentsInformation  etc…  Return string data or false  $this->context will have any context metadataCode

 fwrite  file_put_contentsInformation  get in a string of data to deal with  return how many bytes you wroteCode

 feof  file_get_contents  freadInformation  etc…  Return true or false  $this->context will have any context metadataCode

 fclose  file_get_contentsInformation  Don’t return anything  any cleanup should go hereCode

 fstat calls stream_stat EVERYTHING ELSE uses url_stat Good idea to do both Return an array of data identical to stat()

 stream_seek stream_tell stream_flush

 mkdir rmdir dir_closedir dir_opendir dir_readdir dir_rewinddir

 stream_lock stream_cast rename unlink

Create a custom wrapper for any kind of network or shared memory storage you want (except s3 which is way overdone)Implement at least the basics – extra points for more features

Wrapper for wincache (btw, porting this to apc would be a breeze)Does basics + seek + flush (since we’re caching) + rename + unlinkNo directories

Use Case land – when streamsmake sense

 Data in s3 Data locally during development Easy switch out if alternative storage is ever desired Storing image files

 Existing Zend Framework Code Register the s3:// wrapper Use a configuration setting for the stream to use for all images on the system

 Store and edit template files in a database Have the snappiness of including from disk Minimal Configuration

 db:// stream simple stream wrapper that looks for the template in the db, and writes it to the filesystem before returning the data The cached location is FIRST in the include path, so if it fails, the db stream gets hit

 Talk to mercurial (hg binary) hg communicates via command line continue to pipe additional commands

 Use proc_open to keep a pipe to the binary going Pass commands through stdin pipe as necessary Abstract this out to other binaries that are used by the system

1. Name 3 Built in PHP streams.2. What is a Context? A Wrapper? A Stream?3. How do you identify a stream?4. Name two extensions that provide additional PHP streams.

 http://php.net/streams http://php.net/filesystem http://ciaranmcnulty.com/blog/2009/04/ simplifying-file-operations-using-php- stream-wrappers

Because everyone needs to rot13a file they open on the fly

 Performs operations on stream data Can be prepended or appended (even on the fly) Can be attached to read or write When a filter is added for read and write, two instances of the filter are created.

 Data has an input and output state When reading in chunks, you may need to cache in between reads to make filters useful Use the right tool for the job

 string filters › string.rot13 › string.toupper › string.tolower › string.strip_tags

 convert filters › convert.*  base64-encode  base64-decode  quoted-printable-encode  quoted-printable-decode dechunk › decode remote HTTP chunked encoding streams consumed › eats data (that’s all it does)

 bzip.compress and bzip.compress convert.iconv.* zlib.inflate and zlib.deflate mcrypt.* and mdecrypt.*

 Extend an internal class php_user_filter It’s not abstract… Yes that’s a horrible name Remember this pre-dates php 5.0 decisions

 onCreate  basically a constructor  Called every time PHP needs a new filterInformation (on every stream)  return true or falseCode

 php_user_filter › $this->filtername › $this->params › $this->stream

 onClose  basically a destructorInformation  no returnCode

 MUST return › PSFS_PASS_ON › PSFS_FEED_MEInformation › PSFS_ERR_FATAL  You get buckets of data and do stuff to themCode

 $in and $out are “bucket brigades” containing opaque “buckets” of data You can only touch buckets and brigades with the stream_bucket_* functions You get a bucket using stream_bucket_make_writeable

 Given a list of bad words (we’ll use the 7 bad words), write a filter to remove them from text Given a commonly misspelled word, fix the spelling in the text

 I only did the bad words one, and created an extremely naïve regex that stripped the “bad” words from whatever text it finds. It buffers the entirety of the text before doing the replacement – this could be done by looking for word boundaries and doing it piecemeal to improve performance

1. What term is used to describe data handling in filters?2. Name two built in filters you should be using and why.3. What is the default mode filters are appended with?4. What is the difference between appending and prepending a filter?

 http://php.net/streams http://php.net/filters

Putter about the network with me

 Socket › Bidirectional network stream that speaks a protocol Transport › Tells a network stream how to communicate Wrapper › Tells a stream how to handle specific protocols and encodings

 Network Stream, Network Transport, Socket Transport Slightly different behavior from a file stream Bi-directional data

 Sockets block › stream_set_blocking › stream_set_timeout › stream_select feof means “connection_closed”? huge reads or writes (think 8K) stream_get_meta_data is READ ONLY

 New APIS in streams and filesystem functions are replacements Extension is old and not really kept up to date (bit rot) Extension is more low level stream_socket_server stream_socket_client

 tcp udp unix udg SSL extension › ssl › sslv2 › sslv3 › tls

 Given two files of quotes, write a server with PHP streams methods to return random quotes, optionally allow client to pick which file to retrieve quotes from Given a simple tcp server that will return a random quote – make a client that pulls quotes for users

 socket_server.php – uses stream_socket_server and stream_accept socket_client.php – uses stream_socket_client and a bit of loop magic to make a little “cli” app

1. How is a socket different from a stream?2. What transports does PHP provide by default?3. Name the two most commonly used stream socket functions.4. How can a user add additional transports to PHP?

 http://php.net/streams http://php.net/transports http://wikipedia.org/wiki/Unix_domain_s ocket http://tools.ietf.org/html/rfc1122

 Set of interfaces for streams Improved based filter class Wrappers for chmod and touch More tests! Any you have?

 http://emsmith.net http://joind.in/3439 auroraeosrose@gmail.com IRC – freenode – auroraeosrose #php-gtk #coapp

Writing and using php streams and sockets tek11

by Elizabeth Smith on Jan 09, 2012

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Writing and using php streams and sockets tek11 — Presentation Transcript