Given at php tek 2

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

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

4.  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

5. Abstracting I/O

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

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

8. Stream
Contexts
Stream Stream
ALL IO
Filter Wrapper

9.  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

10.  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

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

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

15. Streams available by default

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

17.  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://

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

22.  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)

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

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

27. Userland Filters and Streams

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

29.  fopen
 file_get_contents
Information
 Return true or false
 $this->context will have any context
metadata
Code

30.  fread
 fgets
 file_get_contents
Information
 etc…
 Return string data or false
 $this->context will have any context
metadata
Code

31.  fwrite
 file_put_contents
Information
 get in a string of data to deal with
 return how many bytes you wrote
Code

32.  feof
 file_get_contents
 fread
Information
 etc…
 Return true or false
 $this->context will have any context
metadata
Code

33.  fclose
 file_get_contents
Information
 Don’t return anything
 any cleanup should go here
Code

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

35.  stream_seek
 stream_tell
 stream_flush

36.  mkdir
 rmdir
 dir_closedir
 dir_opendir
 dir_readdir
 dir_rewinddir

37.  stream_lock
 stream_cast
 rename
 unlink

38. 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

39. Wrapper for wincache (btw, porting this to
apc would be a breeze)
Does basics + seek + flush (since we’re
caching) + rename + unlink
No directories

40. Use Case land – when streams
make sense

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

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

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

44.  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

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

46.  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

47. 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.

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

50. Because everyone needs to rot13
a file they open on the fly

51.  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.

53.  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

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

55.  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)

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

57.  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

58.  onCreate
 basically a constructor
 Called every time PHP needs a new filter
Information
(on every stream)
 return true or false
Code

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

60.  onClose
 basically a destructor
Information
 no return
Code

61.  MUST return
› PSFS_PASS_ON
› PSFS_FEED_ME
Information › PSFS_ERR_FATAL
 You get buckets of data and do stuff to
them
Code

63.  $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

64.  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

65.  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

67. 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?

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

69. Putter about the network with me

70.  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

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

72.  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

73.  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

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

76.  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

77.  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

78. 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?

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

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

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