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| Network.CGI | | Portability | non-portable (uses Control.Monad.State) | | Stability | experimental | | Maintainer | bjorn@bringert.net |
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| Description |
Simple Library for writing CGI programs.
See http://hoohoo.ncsa.uiuc.edu/cgi/interface.html for the
CGI specification.
This version of the library is for systems with version 2.0 or greater
of the network package. This includes GHC 6.6 and later. For older
systems, see http://www.cs.chalmers.se/~bringert/darcs/cgi-compat/doc/
Based on the original Haskell binding for CGI:
Original Version by Erik Meijer mailto:erik@cs.ruu.nl.
Further hacked on by Sven Panne mailto:sven.panne@aedion.de.
Further hacking by Andy Gill mailto:andy@galconn.com.
A new, hopefully more flexible, interface
and support for file uploads by Bjorn Bringert mailto:bjorn@bringert.net.
Here is a simple example, including error handling (not that there is
much that can go wrong with Hello World):
import Network.CGI
cgiMain :: CGI CGIResult
cgiMain = output "Hello World!"
main :: IO ()
main = runCGI (handleErrors cgiMain)
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| Synopsis |
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| class Monad m => MonadCGI m | | | data CGIT m a | | | data CGIResult | | | type CGI a = CGIT IO a | | | runCGI :: MonadIO m => CGIT m CGIResult -> m () | | | throwCGI :: (MonadCGI m, MonadIO m) => Exception -> m a | | | catchCGI :: CGI a -> (Exception -> CGI a) -> CGI a | | | tryCGI :: CGI a -> CGI (Either Exception a) | | | handleExceptionCGI :: CGI a -> (Exception -> CGI a) -> CGI a | | | handleErrors :: CGI CGIResult -> CGI CGIResult | | | logCGI :: MonadIO m => String -> m () | | | output :: MonadCGI m => String -> m CGIResult | | | outputFPS :: MonadCGI m => ByteString -> m CGIResult | | | outputNothing :: MonadCGI m => m CGIResult | | | redirect :: MonadCGI m => String -> m CGIResult | | | setHeader :: MonadCGI m => String -> String -> m () | | | setStatus :: MonadCGI m => Int -> String -> m () | | | outputError :: (MonadCGI m, MonadIO m) => Int -> String -> [String] -> m CGIResult | | | outputException :: (MonadCGI m, MonadIO m) => Exception -> m CGIResult | | | outputNotFound :: (MonadIO m, MonadCGI m) => String -> m CGIResult | | | outputMethodNotAllowed :: (MonadIO m, MonadCGI m) => [String] -> m CGIResult | | | outputInternalServerError :: (MonadIO m, MonadCGI m) => [String] -> m CGIResult | | | getInput :: MonadCGI m => String -> m (Maybe String) | | | getInputFPS :: MonadCGI m => String -> m (Maybe ByteString) | | | readInput :: (Read a, MonadCGI m) => String -> m (Maybe a) | | | getInputs :: MonadCGI m => m [(String, String)] | | | getInputNames :: MonadCGI m => m [String] | | | getMultiInput :: MonadCGI m => String -> m [String] | | | getInputFilename :: MonadCGI m => String -> m (Maybe String) | | | getInputContentType :: MonadCGI m => String -> m (Maybe String) | | | getVar :: MonadCGI m => String -> m (Maybe String) | | | getVarWithDefault :: MonadCGI m => String -> String -> m String | | | getVars :: MonadCGI m => m [(String, String)] | | | serverName :: MonadCGI m => m String | | | serverPort :: MonadCGI m => m Int | | | requestMethod :: MonadCGI m => m String | | | pathInfo :: MonadCGI m => m String | | | pathTranslated :: MonadCGI m => m String | | | scriptName :: MonadCGI m => m String | | | queryString :: MonadCGI m => m String | | | remoteHost :: MonadCGI m => m (Maybe String) | | | remoteAddr :: MonadCGI m => m String | | | authType :: MonadCGI m => m (Maybe String) | | | remoteUser :: MonadCGI m => m (Maybe String) | | | requestContentType :: MonadCGI m => m (Maybe String) | | | requestContentLength :: MonadCGI m => m (Maybe Int) | | | requestHeader :: MonadCGI m => String -> m (Maybe String) | | | progURI :: MonadCGI m => m URI | | | queryURI :: MonadCGI m => m URI | | | requestURI :: MonadCGI m => m URI | | | data ContentType = ContentType {} | | | showContentType :: ContentType -> String | | | parseContentType :: Monad m => String -> m ContentType | | | data Cookie = Cookie {} | | | newCookie :: String -> String -> Cookie | | | getCookie :: MonadCGI m => String -> m (Maybe String) | | | readCookie :: (Read a, MonadCGI m) => String -> m (Maybe a) | | | setCookie :: MonadCGI m => Cookie -> m () | | | deleteCookie :: MonadCGI m => Cookie -> m () | | | formEncode :: [(String, String)] -> String | | | urlEncode :: String -> String | | | formDecode :: String -> [(String, String)] | | | urlDecode :: String -> String |
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| CGI monad
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| class Monad m => MonadCGI m |
| The class of CGI monads. Most CGI actions can be run in
any monad which is an instance of this class, which means that
you can use your own monad transformers to add extra functionality.
| |  Instances | |
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| data CGIT m a |
| The CGIT monad transformer.
| | Instances | |
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| data CGIResult |
| The result of a CGI program.
| | Instances | |
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| type CGI a = CGIT IO a |
| A simple CGI monad with just IO.
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| runCGI :: MonadIO m => CGIT m CGIResult -> m () |
| Run a CGI action. Typically called by the main function.
Reads input from stdin and writes to stdout. Gets
CGI environment variables from the program environment.
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| Error handling
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| throwCGI :: (MonadCGI m, MonadIO m) => Exception -> m a |
| Throw an exception in a CGI monad. The monad is required to be
a MonadIO, so that we can use throwIO to guarantee ordering.
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| catchCGI :: CGI a -> (Exception -> CGI a) -> CGI a |
| Catches any expection thrown by a CGI action, and uses the given
exception handler if an exception is thrown.
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| tryCGI :: CGI a -> CGI (Either Exception a) |
| Catches any exception thrown by an CGI action, and returns either
the exception, or if no exception was raised, the result of the action.
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| handleExceptionCGI :: CGI a -> (Exception -> CGI a) -> CGI a |
| Deprecated version of catchCGI. Use catchCGI instead.
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| handleErrors :: CGI CGIResult -> CGI CGIResult |
Catches any exception thrown by the given CGI action,
returns an error page with a 500 Internal Server Error,
showing the exception information, and logs the error.
Typical usage:
cgiMain :: CGI CGIResult
cgiMain = ...
main :: IO ()
main = runCGI (handleErrors cgiMain)
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| Logging
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| logCGI :: MonadIO m => String -> m () |
| Logs some message using the server's logging facility.
FIXME: does this have to be more general to support
FastCGI etc? Maybe we should store log messages in the
CGIState?
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| Output
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| output |
| :: MonadCGI m | | | => String | The string to output.
| | -> m CGIResult | | | Output a String. The output is assumed to be text/html, encoded using
ISO-8859-1. To change this, set the Content-type header using
setHeader.
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| outputFPS |
| :: MonadCGI m | | | => ByteString | The string to output.
| | -> m CGIResult | | | Output a ByteString. The output is assumed to be text/html,
encoded using ISO-8859-1. To change this, set the
Content-type header using setHeader.
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| outputNothing :: MonadCGI m => m CGIResult |
| Do not output anything (except headers).
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| redirect |
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| setHeader |
| :: MonadCGI m | | | => String | Header name.
| | -> String | Header value.
| | -> m () | | Add a response header.
Example:
setHeader "Content-type" "text/plain"
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| setStatus |
| :: MonadCGI m | | | => Int | HTTP status code, e.g. 404
| | -> String | HTTP status message, e.g. Not Found
| | -> m () | | | Set the HTTP response status.
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| Error pages
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| outputError |
| :: (MonadCGI m, MonadIO m) | | | => Int | HTTP Status code
| | -> String | Status message
| | -> [String] | Error information
| | -> m CGIResult | | | Output an error page to the user, with the given
HTTP status code in the response. Also logs the error information
using logCGI.
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| outputException :: (MonadCGI m, MonadIO m) => Exception -> m CGIResult |
| Output a 500 Internal Server Error with information from
an Exception.
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| outputNotFound |
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| outputMethodNotAllowed |
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| outputInternalServerError |
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| Input
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| getInput |
| :: MonadCGI m | | | => String | The name of the variable.
| | -> m (Maybe String) | The value of the variable,
or Nothing, if it was not set.
| Get the value of an input variable, for example from a form.
If the variable has multiple values, the first one is returned.
Example:
query <- getInput "query"
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| getInputFPS |
| :: MonadCGI m | | | => String | The name of the variable.
| | -> m (Maybe ByteString) | The value of the variable,
or Nothing, if it was not set.
| | Like getInput, but returns a ByteString.
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| readInput |
| :: (Read a, MonadCGI m) | | | => String | The name of the variable.
| | -> m (Maybe a) | Nothing if the variable does not exist
or if the value could not be interpreted
at the desired type.
| | Same as getInput, but tries to read the value to the desired type.
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| getInputs :: MonadCGI m => m [(String, String)] |
| Get the names and values of all inputs.
Note: the same name may occur more than once in the output,
if there are several values for the name.
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| getInputNames :: MonadCGI m => m [String] |
| Get the names of all input variables.
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| getMultiInput |
| :: MonadCGI m | | | => String | The name of the variable.
| | -> m [String] | The values of the variable,
or the empty list if the variable was not set.
| Get all the values of an input variable, for example from a form.
This can be used to get all the values from form controls
which allow multiple values to be selected.
Example:
vals <- getMultiInput "my_checkboxes"
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| getInputFilename |
| :: MonadCGI m | | | => String | The name of the variable.
| | -> m (Maybe String) | The file name corresponding to the
input, if there is one.
| | Get the file name of an input.
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| getInputContentType |
| :: MonadCGI m | | | => String | The name of the variable.
| | -> m (Maybe String) | The content type, formatted as a string.
| | Get the content-type of an input, if the input exists, e.g. image/jpeg.
For non-file inputs, this function returns text/plain.
You can use parseContentType to get a structured
representation of the the content-type value.
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| Environment
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| getVar |
| :: MonadCGI m | | | => String | The name of the variable.
| | -> m (Maybe String) | | Get the value of a CGI environment variable. Example:
remoteAddr <- getVar "REMOTE_ADDR"
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| getVarWithDefault |
| :: MonadCGI m | | | => String | The name of the variable.
| | -> String | Default value
| | -> m String | |
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| getVars :: MonadCGI m => m [(String, String)] |
| Get all CGI environment variables and their values.
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| serverName :: MonadCGI m => m String |
| The server's hostname, DNS alias, or IP address as it would
appear in self-referencing URLs.
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| serverPort :: MonadCGI m => m Int |
| The port number to which the request was sent.
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| requestMethod :: MonadCGI m => m String |
| The method with which the request was made.
For HTTP, this is "GET", "HEAD", "POST", etc.
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| pathInfo :: MonadCGI m => m String |
The extra path information, as given by the client.
This is any part of the request path that follows the
CGI program path.
If the string returned by this function is not empty,
it is guaranteed to start with a '/'.
Note that this function returns an unencoded string.
Make sure to percent-encode any characters
that are not allowed in URI paths before using the result of
this function to construct a URI.
See progURI, queryURI and requestURI for a higher-level
interface.
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| pathTranslated :: MonadCGI m => m String |
| The path returned by pathInfo, but with virtual-to-physical
mapping applied to it.
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| scriptName :: MonadCGI m => m String |
A virtual path to the script being executed,
used for self-referencing URIs.
Note that this function returns an unencoded string.
Make sure to percent-encode any characters
that are not allowed in URI paths before using the result of
this function to construct a URI.
See progURI, queryURI and requestURI for a higher-level
interface.
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| queryString :: MonadCGI m => m String |
| The information which follows the ? in the URL which referenced
this program. This is the percent-encoded query information.
For most normal uses, getInput and friends are probably
more convenient.
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| remoteHost :: MonadCGI m => m (Maybe String) |
| The hostname making the request. If the server does not have
this information, Nothing is returned. See also remoteAddr.
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| remoteAddr :: MonadCGI m => m String |
| The IP address of the remote host making the request.
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| authType :: MonadCGI m => m (Maybe String) |
| If the server supports user authentication, and the script is
protected, this is the protocol-specific authentication method
used to validate the user.
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| remoteUser :: MonadCGI m => m (Maybe String) |
| If the server supports user authentication, and the script is
protected, this is the username they have authenticated as.
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| requestContentType :: MonadCGI m => m (Maybe String) |
| For queries which have attached information, such as
HTTP POST and PUT, this is the content type of the data.
You can use parseContentType to get a structured
representation of the the content-type value.
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| requestContentLength :: MonadCGI m => m (Maybe Int) |
| For queries which have attached information, such as
HTTP POST and PUT, this is the length of the content
given by the client.
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| requestHeader :: MonadCGI m => String -> m (Maybe String) |
Gets the value of the request header with the given name.
The header name is case-insensitive.
Example:
requestHeader "User-Agent"
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| Program and request URI
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| progURI :: MonadCGI m => m URI |
Attempts to reconstruct the absolute URI of this program.
This does not include
any extra path information or query parameters. See
queryURI for that.
If the server is rewriting request URIs, this URI can
be different from the one requested by the client.
See also requestURI.
Characters in the components of the returned URI are escaped
when needed, as required by Network.URI.
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| queryURI :: MonadCGI m => m URI |
Like progURI, but the returned URI also includes
any extra path information, and any query parameters.
If the server is rewriting request URIs, this URI can
be different from the one requested by the client.
See also requestURI.
Characters in the components of the returned URI are escaped
when needed, as required by Network.URI.
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| requestURI :: MonadCGI m => m URI |
Attempts to reconstruct the absolute URI requested by the client,
including extra path information and query parameters.
If no request URI rewriting is done, or if the web server does not
provide the information needed to reconstruct the request URI,
this function returns the same value as queryURI.
Characters in the components of the returned URI are escaped
when needed, as required by Network.URI.
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| Content type
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| data ContentType |
| A MIME media type value.
The Show instance is derived automatically.
Use showContentType to obtain the standard
string representation.
See http://www.ietf.org/rfc/rfc2046.txt for more
information about MIME media types.
| | Constructors | | ContentType | | | ctType :: String | The top-level media type, the general type
of the data. Common examples are
"text", "image", "audio", "video",
"multipart", and "application".
| | ctSubtype :: String | The media subtype, the specific data format.
Examples include "plain", "html",
"jpeg", "form-data", etc.
| | ctParameters :: [(String, String)] | Media type parameters. On common example is
the charset parameter for the "text"
top-level type, e.g. ("charset","ISO-8859-1").
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| showContentType :: ContentType -> String |
| Produce the standard string representation of a content-type,
e.g. "text/html; charset=ISO-8859-1".
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| parseContentType :: Monad m => String -> m ContentType |
| Parse the standard representation of a content-type.
If the input cannot be parsed, this function calls
fail with a (hopefully) informative error message.
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| Cookies
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| data Cookie |
| Contains all information about a cookie set by the server.
| | Constructors | | Cookie | | | cookieName :: String | Name of the cookie.
| | cookieValue :: String | Value of the cookie.
| | cookieExpires :: (Maybe CalendarTime) | Expiry date of the cookie. If Nothing, the
cookie expires when the browser sessions ends.
If the date is in the past, the client should
delete the cookie immediately.
| | cookieDomain :: (Maybe String) | The domain suffix to which this cookie will be sent.
| | cookiePath :: (Maybe String) | The path to which this cookie will be sent.
| | cookieSecure :: Bool | True if this cookie should only be sent using
secure means.
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| newCookie |
| :: String | Name
| | -> String | Value
| | -> Cookie | Cookie
| | Construct a cookie with only name and value set.
This client will expire when the browser sessions ends,
will only be sent to the server and path which set it
and may be sent using any means.
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| getCookie |
| :: MonadCGI m | | | => String | The name of the cookie.
| | -> m (Maybe String) | Nothing if the cookie does not exist.
| | Get the value of a cookie.
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| readCookie |
| :: (Read a, MonadCGI m) | | | => String | The name of the cookie.
| | -> m (Maybe a) | Nothing if the cookie does not exist
or if the value could not be interpreted
at the desired type.
| | Same as getCookie, but tries to read the value to the desired type.
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| setCookie :: MonadCGI m => Cookie -> m () |
| Set a cookie.
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| deleteCookie :: MonadCGI m => Cookie -> m () |
| Delete a cookie from the client
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| URL encoding
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| formEncode :: [(String, String)] -> String |
| Formats name-value pairs as application/x-www-form-urlencoded.
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| urlEncode :: String -> String |
| Converts a single value to the application/x-www-form-urlencoded encoding.
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| formDecode :: String -> [(String, String)] |
| Gets the name-value pairs from application/x-www-form-urlencoded data.
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| urlDecode :: String -> String |
| Converts a single value from the
application/x-www-form-urlencoded encoding.
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| Produced by Haddock version 0.8 |
