[//000000001]: # (rest \- A framework for RESTful web services) [//000000002]: # (Generated from file 'rest\.man' by tcllib/doctools with format 'markdown') [//000000003]: # (rest\(n\) 1\.7 tcllib "A framework for RESTful web services")
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# NAME rest \- define REST web APIs and call them inline or asychronously # Table Of Contents - [Table Of Contents](#toc) - [Synopsis](#synopsis) - [Description](#section1) - [Simple usage](#section2) - [Interface usage](#section3) - [Examples](#section4) - [INCLUDED](#section5) - [TLS](#section6) - [TLS Security Considerations](#section7) - [Bugs, Ideas, Feedback](#section8) # SYNOPSIS package require Tcl 8\.5 9 package require rest ?1\.7? [__::rest::simple__ *url* *query* ?*config*? ?*body*?](#1) [__::rest::get__ *url* *query* ?*config*? ?*body*?](#2) [__::rest::post__ *url* *query* ?*config*? ?*body*?](#3) [__::rest::patch__ *url* *query* ?*config*? ?*body*?](#4) [__::rest::head__ *url* *query* ?*config*? ?*body*?](#5) [__::rest::put__ *url* *query* ?*config*? ?*body*?](#6) [__::rest::delete__ *url* *query* ?*config*? ?*body*?](#7) [__::rest::save__ *name* *file*](#8) [__::rest::describe__ *name*](#9) [__::rest::parameters__ *url* ?*key*?](#10) [__::rest::parse\_opts__ *static* *required* *optional* *words*](#11) [__::rest::substitute__ *string* *var*](#12) [__::rest::create\_interface__ *name*](#13) # DESCRIPTION There are two types of usage this package supports: *simple calls*, and complete *interfaces*\. In an *interface* you specify a set of rules and then the package builds the commands which correspond to the REST methods\. These commands can have many options such as input and output transformations and data type specific formatting\. This results in a cleaner and simpler script\. On the other hand, while a *simple call* is easier and quicker to implement it is also less featureful\. It takes the url and a few options about the command and returns the result directly\. Any formatting or checking is up to rest of the script\. # Simple usage In simple usage you make calls using the http method procedures and then check or process the returned data yourself - __::rest::simple__ *url* *query* ?*config*? ?*body*? - __::rest::get__ *url* *query* ?*config*? ?*body*? - __::rest::post__ *url* *query* ?*config*? ?*body*? - __::rest::patch__ *url* *query* ?*config*? ?*body*? - __::rest::head__ *url* *query* ?*config*? ?*body*? - __::rest::put__ *url* *query* ?*config*? ?*body*? - __::rest::delete__ *url* *query* ?*config*? ?*body*? These commands are all equivalent except for the http method used\. If you use __simple__ then the method should be specified as an option in the *config* dictionary\. If that is not done it defaults to __get__\. If a *body* is needed then the *config* dictionary must be present, however it is allowed to be empty\. The *config* dictionary supports the following keys * __auth__ * __content\-type__ * __cookie__ * __error\-body__ * __format__ * __headers__ * __method__ * __timeout__ Two quick examples: Example 1, Yahoo Boss: set appid APPID set search tcl set res [rest::get http://boss.yahooapis.com/ysearch/web/v1/$search [list appid $appid]] set res [rest::format_json $res] Example 2, Twitter: set url http://twitter.com/statuses/update.json set query [list status $text] set res [rest::simple $url $query { method post auth {basic user password} format json }] # Interface usage An interface to a REST API consists of a series of definitions of REST calls contained in an array\. The name of that array becomes a namespace containing the defined commands\. Each key of the array specifies the name of the call, with the associated configuration a dictionary, i\.e\. key/value pairs\. The acceptable keys, i\.e\. legal configuration options are described below\. After creating the definitions in the array simply calling __rest::create\_interface__ with the array as argument will then create the desired commands\. Example, Yahoo Weather: package require rest set yweather(forecast) { url http://weather.yahooapis.com/forecastrss req_args { p: } opt_args { u: } } rest::create_interface yweather puts [yweather::forecast -p 94089] - __::rest::save__ *name* *file* This command saves a copy of the dynamically created procedures for all the API calls specified in the array variable *name* to the *file*, for later loading\. The result of the command is the empty string - __::rest::describe__ *name* This command prints a description of all API calls specified in the array variable *name* to the channel __stdout__\. The result of the command is the empty string\. - __::rest::parameters__ *url* ?*key*? This command parses an *url* query string into a dictionary and returns said dictionary as its result\. If *key* is specified the command will not return the entire dictionary, but only the value of that *key*\. - __::rest::parse\_opts__ *static* *required* *optional* *words* This command implements a custom parserfor command options\. * dict *static* A dictionary of options and their values that are always present in the output\. * list *required* A list of options that must be supplied by *words* * list *optional* A list of options that may appear in the *words*, but are not required\. The elements must be in one of three forms: + name The option may be present or not, no default\. + name: When present the option requires an argument\. + name:value When not present use __value__ as default\. * list *words* The words to parse into options and values\. The result of the command is a list containing two elements\. The first element is a dictionary containing the parsed options and their values\. The second element is a list of the remaining words\. - __::rest::substitute__ *string* *var* This command takes a *string*, substitutes values for any option identifiers found inside and returns the modified string as its results\. The values to substitute are found in the variable *var*, which is expected to contain a dictionary mapping from the option identifiers to replace to their values\. *Note* that option identifiers which have no key in *var* are replaced with the empty string\. The option identifiers in *string* have to follow the syntax __%\.\.\.%__ where __\.\.\.__ may contain any combination of lower\-case alphanumeric characters, plus underscore, colon and dash\. - __::rest::create\_interface__ *name* This command creates procedures for all the API calls specified in the array variable *name*\. The name of that array becomes a namespace containing the defined commands\. Each key of the array specifies the name of the call, with the associated configuration a dictionary, i\.e\. key/value pairs\. The legal keys and their meanings are: * __url__ The value of this *required* option must be the target of the http request\. * __description__ The value of this option must be a short string describing the call\. Default to the empty string, if not specified\. Used only by __::rest::describe__\. * __body__ The value of this option indicates if arguments are required for the call's request body or not\. The acceptable values are listed below\. Defaults to __optional__ if not specified\. + __none__ The call has no request body, none must be supplied\. + __optional__ A request body can be supplied, but is not required\. + __required__ A request body must be supplied\. + __argument__ This value must be followed by the name of an option, treating the entire string as a list\. The request body will be used as the value of that option\. + __mime\_multipart__ A request body must be supplied and will be interpreted as each argument representing one part of a mime/multipart document\. Arguments must be lists containing 2 elements, a list of header keys and values, and the mime part body, in this order\. + __mime\_multipart/__ Same as mime\_multipart, but the __Content\-Type__ header is set to __multipart/__\. * __method__ The value of this option must be the name of the HTTP method to call on the url\. Defaults to GET, if not specified\. The acceptable values are __GET__, __POST__, and __PUT__, regardless of letter\-case\. * __copy__ When present the value of this option specifies the name of a previously defined call\. The definition of that call is copied to the current call, except for the options specified by the current call itself\. * __unset__ When present the value of this option contains a list of options in the current call\. These options are removed from the definition\. Use this after __copy__ing an existing definition to remove options, instead of overriding their value\. * __headers__ Specification of additional header fields\. The value of this option must be a dictionary, interpreted to contain the new header fields and their values\. The default is to not add any additional headers\. * __content\-type__ The value of this option specifies the content type for the request data\. * __req\_args__ The value of this option is a list naming the required arguments of the call\. Names ending in a colon will require a value\. * __opt\_args__ The value of this option a list naming the arguments that may be present for a call but are not required\. * __static\_args__ The value of this option a list naming the arguments that are always the same\. No sense in troubling the user with these\. A leading dash \(__\-__\) is allowed but not required to maintain consistency with the command line\. * __auth__ The value of this option specifies how to authenticate the calls\. No authentication is done if the option is not specified\. + __basic__ The user may configure the *basic authentication* by overriding the procedure __basic\_auth__ in the namespace of interface\. This procedure takes two arguments, the username and password, in this order\. + __bearer__ The user may configure a bearer token as authentication\. The value is the token passed to the HTTP authorization header\. + __sign__ The value must actually be a list with the second element the name of a procedure which will be called to perform request signing\. * __callback__ If this option is present then the method will be created as an *async* call\. Such calls will return immediately with the value of the associated http token instead of the call's result\. The event loop must be active to use this option\. The value of this option is treated as a command prefix which is invoked when the HTTP call is complete\. The prefix will receive at least two additional arguments, the name of the calling procedure and the status of the result \(one of __OK__ or __ERROR__\), in this order\. In case of __OK__ a third argument is added, the data associated with the result\. If and only if the __ERROR__ is a redirection, the location redirected to will be added as argument\. Further, if the configuration key __error\-body__ is set to __true__ the data associated with the result will be added as argument as well\. The http request header will be available in that procedure via __upvar token token__\. * __cookie__ The value of this option is a list of cookies to be passed in the http header\. This is a shortcut to the __headers__ option\. * __input\_transform__ The value of this option is a command prefix or script to perform a transformation on the query before invoking the call\. A script transform is wrapped into an automatically generated internal procedure\. If not specified no transformation is done\. The command \(prefix\) must accept a single argument, the query \(a dictionary\) to transform, and must return the modified query \(again as dictionary\) as its result\. The request body is accessible in the transform command via __upvar body body__\. * __format__ * __result__ The value of this option specifies the format of the returned data\. Defaults to __auto__ if not specified\. The acceptable values are: + __auto__ Auto detect between __xml__ and __json__\. + __discard__ + __json__ + __raw__ + __rss__ This is formatted as a special case of __xml__\. + __tdom__ + __xml__ * __pre\_transform__ The value of this option is a command prefix or script to perform a transformation on the result of a call \(*before* the application of the output transform as per __format__\)\. A script transform is wrapped into an automatically generated internal procedure\. If not specified no transformation is done\. The command \(prefix\) must accept a single argument, the result to transform, and must return the modified result as its result\. The http request header is accessible in the transform command via __upvar token token__ * __post\_transform__ The value of this option is a command prefix or script to perform a transformation on the result of a call \(*after* the application of the output transform as per __format__\)\. A script transform is wrapped into an automatically generated internal procedure\. If not specified no transformation is done\. The command \(prefix\) must accept a single argument, the result to transform, and must return the modified result as its result\. The http request header is accessible in the transform command via __upvar token token__ * __check\_result__ The value of this option must be list of two expressions, either of which may be empty\. The first expression is checks the OK condition, it must return __true__ when the result is satisfactory, and __false__ otherwise\. The second expression is the ERROR condition, it must return __false__ unless there is an error, then it has to return __true__\. * __error\_body__ The value of this option determines whether to return the response when encountering an HTTP error, or not\. The default is to not return the response body on error\. See __callback__ above for more information\. * __timeout__ The value of this option determines whether to set a timeout on the HTTP call\. By default, no timeout is set\. Timeout value is accepted in milliseconds\. # Examples Yahoo Geo: set ygeo(parse) { url http://wherein.yahooapis.com/v1/document method post body { arg documentContent } } ygeo::parse "san jose ca" # "san jose ca" will be interpreted as if it were specified as the -documentContent option Google Docs: set gdocs(upload) { url http://docs.google.com/feeds/default/private/full body mime_multipart } gdocs::upload [list {Content-Type application/atom+xml} $xml] [list {Content-Type image/jpeg} $filedata] Delicious: set delicious(updated) { url https://api.del.icio.us/v1/posts/update auth basic } rest::create_interface flickr flickr::basic_auth username password Flickr: set flickr(auth.getToken) { url http://api.flickr.com/services/rest/ req_args { api_key: secret: } auth { sign do_signature } } rest::create_interface flickr proc ::flickr::do_signature {query} { # perform some operations on the query here return $query } # INCLUDED The package provides functional but incomplete implementations for the following services: - __del\.icio\.us__ - __facebook__ - __flickr__ - __twitter__ - __google calendar__ - __yahoo boss__ - __yahoo weather__ Please either read the package's implementation, or use __rest::describe__ after loading it for their details\. Do not forget developers' documentation on the respective sites either\. # TLS The __rest__ package can be used with *[https](\.\./\.\./\.\./\.\./index\.md\#https)*\-secured services, by requiring the __[TLS](\.\./\.\./\.\./\.\./index\.md\#tls)__ package and then registering it with the __[http](\.\./\.\./\.\./\.\./index\.md\#http)__ package it is sitting on top of\. Example package require tls http::register https 443 ::tls::socket # TLS Security Considerations This package uses the __[TLS](\.\./\.\./\.\./\.\./index\.md\#tls)__ package to handle the security for __https__ urls and other socket connections\. Policy decisions like the set of protocols to support and what ciphers to use are not the responsibility of __[TLS](\.\./\.\./\.\./\.\./index\.md\#tls)__, nor of this package itself however\. Such decisions are the responsibility of whichever application is using the package, and are likely influenced by the set of servers the application will talk to as well\. For example, in light of the recent [POODLE attack](http://googleonlinesecurity\.blogspot\.co\.uk/2014/10/this\-poodle\-bites\-exploiting\-ssl\-30\.html) discovered by Google many servers will disable support for the SSLv3 protocol\. To handle this change the applications using __[TLS](\.\./\.\./\.\./\.\./index\.md\#tls)__ must be patched, and not this package, nor __[TLS](\.\./\.\./\.\./\.\./index\.md\#tls)__ itself\. Such a patch may be as simple as generally activating __tls1__ support, as shown in the example below\. package require tls tls::init -tls1 1 ;# forcibly activate support for the TLS1 protocol ... your own application code ... # Bugs, Ideas, Feedback This document, and the package it describes, will undoubtedly contain bugs and other problems\. Please report such in the category *rest* of the [Tcllib Trackers](http://core\.tcl\.tk/tcllib/reportlist)\. Please also report any ideas for enhancements you may have for either package and/or documentation\. When proposing code changes, please provide *unified diffs*, i\.e the output of __diff \-u__\. Note further that *attachments* are strongly preferred over inlined patches\. Attachments can be made by going to the __Edit__ form of the ticket immediately after its creation, and then using the left\-most button in the secondary navigation bar\.