CAPTCHA Adapters
The following adapters are shipped with Zend Framework by default.
Zend_Captcha_Word
Zend_Captcha_Word is an abstract adapter that serves as the base
class for most other CAPTCHA adapters. It provides mutators for
specifying word length, session TTL, the session namespace object
to use, and the session namespace class to use for persistence if
you do not wish to use Zend_Session_Namespace.
Zend_Captcha_Word encapsulates validation logic.
By default, the word length is 8 characters, the session timeout is
5 minutes, and Zend_Session_Namespace is used for persistence
(using the namespace "Zend_Form_Captcha_<captcha ID>").
In addition to the methods required by the
Zend_Captcha_Adapter interface,
Zend_Captcha_Word exposes the following methods:
setWordLen($length) and
getWordLen() allow you to specify the length of the
generated "word" in characters, and to retrieve the current value.
setTimeout($ttl) and getTimeout()
allow you to specify the time-to-live of the session token, and
to retrieve the current value. $ttl should be
specified in seconds.
setSessionClass($class) and
getSessionClass() allow you to specify an
alternate Zend_Session_Namespace implementation to
use to persist the CAPTCHA token and to retrieve the
current value.
getId() allows you to retrieve the current token
identifier.
getWord() allows you to retrieve the generated
word to use with the CAPTCHA. It will generate the word for you
if none has been generated yet.
setSession(Zend_Session_Namespace $session) allows
you to specify a session object to use for persisting the
CAPTCHA token. getSession() allows you
to retrieve the current session object.
All word CAPTCHAs allow you to pass an array of options to the
constructor, or, alternately, pass them to
setOptions(). You can also pass a
Zend_Config object to setConfig(). By
default, the wordLen, timeout, and
sessionClass keys may all be used. Each concrete
implementation may define additional keys or utilize the options in
other ways.
Note:
Zend_Captcha_Word is an abstract class and may not be
instantiated directly.
Zend_Captcha_Dumb
The Zend_Captch_Dumb adapter is mostly self-descriptive. It
provides a random string that must be typed in reverse to validate. As such, it's
not a good CAPTCHA solution and should only be used for
testing. It extends Zend_Captcha_Word.
Zend_Captcha_Figlet
The Zend_Captcha_Figlet adapter utilizes Zend_Text_Figlet to present
a figlet to the user.
Options passed to the constructor will also be passed to the Zend_Text_Figlet object.
See the Zend_Text_Figlet
documentation for details on what configuration options are available.
Zend_Captcha_Image
The Zend_Captcha_Image adapter takes the generated word and
renders it as an image, performing various skewing permutations to make it
difficult to automatically decipher. It
requires the » GD extension
compiled with TrueType or Freetype support. Currently, the
Zend_Captcha_Image adapter can only generate
PNG images.
Zend_Captcha_Image extends
Zend_Captcha_Word, and additionally exposes the
following methods:
setExpiration($expiration) and
getExpiration() allow you to specify a maximum
lifetime the CAPTCHA image may reside on the filesystem. This is
typically a longer than the session lifetime. Garbage
collection is run periodically each time the CAPTCHA object is
invoked, deleting all images that have expired.
Expiration values should be specified in seconds.
setGcFreq($gcFreq) and getGcFreg()
allow you to specify how frequently garbage collection should
run. Garbage collection will run every 1/$gcFreq
calls. The default is 100.
setFont($font) and getFont() allow
you to specify the font you will use. $font
should be a fully qualified path to the font file.
This value is required; the CAPTCHA will throw an
exception during generation if the font file has not been specified.
setFontSize($fsize) and
getFontSize() allow you to specify the font size in pixels
for generating the CAPTCHA. The default is 24px.
setHeight($height) and getHeight()
allow you to specify the height in pixels of the generated
CAPTCHA image. The default is 50px.
setWidth($width) and getWidth()
allow you to specify the width in pixels of the generated
CAPTCHA image. The default is 200px.
setImgDir($imgDir) and getImgDir()
allow you to specify the directory for storing CAPTCHA images.
The default is "./images/captcha/", relative to the bootstrap
script.
setImgUrl($imgUrl) and getImgUrl()
allow you to specify the relative path to a CAPTCHA image to
use for HTML markup. The default is
"/images/captcha/".
setSuffix($suffix) and getSuffix()
allow you to specify the filename suffix for the CAPTCHA image.
The default is ".png". Note: changing this value will not
change the type of the generated image.
All of the above options may be passed to the
constructor by simply removing the 'set' method prefix and casting
the initial letter to lowercase: "suffix", "height", "imgUrl", etc.
Zend_Captcha_ReCaptcha
The Zend_Captcha_ReCaptcha adapter uses Zend_Service_ReCaptcha
to generate and validate CAPTCHAs. It exposes the following
methods:
setPrivKey($key) and getPrivKey()
allow you to specify the private key to use for the ReCaptcha
service. This must be specified during construction, although it
may be overridden at any point.
setPubKey($key) and getPubKey()
allow you to specify the public key to use with the ReCaptcha
service. This must be specified during construction, although it
may be overridden at any point.
setService(Zend_Service_ReCaptcha $service) and
getService() allow you to set and get
the ReCaptcha service object.