man nwg (3): standard network working group module

STANDARD NETWORK WORKING GROUP MODULE

The Standard Network Working Groupmodule is an original implemtation of the recommendations proposed by the NWG and currently found in the form of Request for Comments(RFC). Most of the objects are used with networking application, with the most common one beeing the Universal Resource Identifier(URI) object.

The uri class
The Uriclass is a base class that parses a Uniform Resource Identifieror uri string and provides methods to access individual component of that uri. The implementation conforms to RFC 3986. The URI components are the scheme, the authority, the path, the query and the fragment. The class also takes care of the character escaping.

const uri (afnix:www:Uri "http://www.afnix.org")

An uri can be broken into several components called the scheme, the authority, the path, optionally the queryand the fragment. The Uriclass provide a method to retrieve each component of the parsed uri.

const uri (afnix:www:Uri "http://www.afnix.org/")
println (uri:get-scheme)    # http
println (uri:get-authority) # www.afnix.org
println (uri:get-path)      # /

Character conversion
The Uriclass performs automatically the character conversion in the input uri. For example, the +character is replaced by a blank. The %character followed by two hexadecimal values is replaced by the corresponding ASCII character. Note that this conversion does now apply to the query string.

Query string
The get-querymethod returns the query string of the uri. The query string starts after the ?character. The query string is a series of key-pair values separated by the &character.

const uri (afnix:www:Uri 
  "http://www.afnix.org?name=hello&value=world")
println (uri:get-query) # name=hello&value=world

The module also provides the UriQueryclass that parses the query string and store the result in the form of a property list. The query string parse is particularly useful when writing automated scripts.

# create a query string object
const qs (afnix:nwg:UriQuery (uri:get-query))
# get the name value
qs:get-value "name"

Managing a cgi request
Managing a cgi request involves primarily the parsing of the requesting uri. The uri generally contains the http referrer as well as parameter which are stored in the form of a query string. However, depending on the cgi method which can be of type GETor POST, the treatment is somewhat different.

Checking the protocol version
In the presence of a cgi protocol, it is always a good idea to check the protocol version, or at least to put an assertion. The protocol version is normally CGI/1.1and is stored in the GATEWAY_INTERFACEenvironment variable.

# check the cgi protocol
assert "CGI/1.1" (
  afnix:sys:get-env "GATEWAY_INTERFACE")

Getting the query string
If the request method is GET, then the query string is available in the environment variable QUERY_STRING. If the request method is POST, the query string is available in the input stream. The length of the query string is given by the CONTENT_LENGTHenvironment variable. The following example illustrates the extraction of the query string.

# check the cgi protocol
assert "CGI/.1" (
  afnix:sys:get-env "GATEWAY_INTERFACE")
# initialize the query string
const query (afnix:sys:get-env "QUERY_STRING")
# get the request method
const rqm (afnix:sys:get-env "REQUEST_METHOD")
# check for a post request and update the query string
if (== rqm "POST") {
  # create a buffer from the content length
  const len (
    Integer (afnix:sys:get-env "CONTENT_LENGTH"))
  # get the standard input stream and read content
  const is  (interp:get-input-stream)
  const buf (is:read len)
  # set the query string
  query:= (buf:to-string)
}

Parsing the query string
The UriQueryclass is designed to parse a cgi query string. Once the string has been parsed, it is possible to perform a query by key since the class operates with a property list.

const query (
  afnix:www:UriQuery "name=hello&value=world")
query:length      # 2
query:get-value "name"  # hello
query:get-value "value" # world

The UriQueryclass is the foundation to build cgi script. When the library is combined with the web application management (wam)service, powerful applications can be built easily.

Special functions
Several dedicated functions are available in the library as a way to ease the object manipulations. Theses functions operate mostly on uri and files as described below.

Uri functions
Several functions are designed to ease the uri manipulation. Most of them operate on the uri name or their associated system name. The normalize-uri-namefunction normalizes a string argument by adding a uri scheme if missing in the original string. If the function detects that the name starts with a host name, the httpscheme is added. If the function detects that the string starts with a path, the filescheme is added. otherwise, the name argument is left untouched. The system-uri-namefunction normalizes the string argument by prioritizing the system name. The function attempts to find a file that match the sring argument and eventually build a uri file scheme. If the file is not fond, the normalization process occurs with the normalize-uri-namefunction.

# normalize a uri name
trans  unm "http://www.afnix.org"
assert unm (
  afnix:nwg:normalize-uri-name unm)
assert unm (
  afnix:nwg:normalize-uri-name "www.afnix.org")
assert unm (
  afnix:nwg:normalize-uri-name "//www.afnix.org")

Mime functions
Mime functions are dedicated to easee the mainpulation of media types or mime. A media type is defined by a string in the form of a type and content value such as text/plain. The mime-value-ppredicate returns true if a string mime value is a valid media type. From a file perspective, the mime-extension-ppredicate returns true if the string extension has a valid media type associated to it. Finally, the extension-to-mimefunction can be used to get the string mime value associated with a file extension.

# check a media type
assert true (afnix:nwg:mime-value-p "text/plain")
# check the mime extension predicate
assert true (afnix:nwg:mime-extension-p "txt")
# check the extension to mime
assert "text/plain" (
  afnix:nwg:extension-to-mime "txt")

HTTP transaction objects
The concept of HTTP transactions is defined in RFC 2616. In the client/server approach, a client issues a request which is answered with a response. A special case arise when the server is asked to perform some extra works, such like executing a script. In this case, the answer is called a reply which is formatted into a response when the server does its job correctly. The nature of the HTTP objects determines how the associated stream behaves. With a HTTP request, the object is filled by reading an input stream when operating on the server side. On the other hand, the request is filled by data when operating on the client side. With a HTTP response, the opposite situation occurs. The HTTP response is filled by reading an input stream when operating on the client side and filled by data when operating on the server side.

HTTP protocol
The HttpProtoclass is a base class designed to handle a HTTP header that is found in both HTTP request and response. The class is built around a property list that is filled either by parsing an input stream or by processing specific methods. The HttpProtodefines also some methods which are often used with a HTTP request or response.

HTTP response
The HttpResponseclass is a class designed to handle a HTTP response. When operating on the client side, the response object is built by reading an input stream. When operating on the server side, the response object is built by calling specific methods.

Creating a server response
A server response is created by specifying the response status code. By default, a HTTP response is created with the default media type text/html. If the media type needs to be changed, it can be passed as the second argument to the response constructor. By default, the empty constructor creates an empty constructor with a valid status code.

#create a valid response
const hr (afnix:nwg:HttpResponse 200)

Once the server response is created, it can be augmented with some headed values. Typically, a server will add some information about the response, such like the content length, the modification time or a tag. The HttpResponseprovides several methods that ease the generation of these header values.

Creating a client response
A client response is created by binding an input stream to a response object. During the construction, the input stream is read and the HTTP protocol header is filled. It is also during this phase that the status code is processed. It is therefore important to ensure that a response object is built correctly before attempting to access it.

# create a client response by stream
const hr (afnix:nwg:HttpResponse is)

Reading a client response
When the response has been created, it is important to check its status code. Most of the time, the response is valid and its content can be read directly. The status-ok-ppredicate returns true if the status code is valid. In such case, a HTTP stream can be built in order to read the response.

# check that a response is valid
if (hr:status-ok-p) {
  # create a http stream
  const rs (afnix:nwg:HttpStream ht is)
  # read the response stream
  while (rs:eos-p) (rs:read)
}

Before reading a http stream, it is important to detect and verify the nature of the response content. The media-type-ppredicate returns true if the media type is defined and the get-media-typemethod returns the response type in the form of a mime code such like text/html. Eventually, the character set associated with the media type can also be detected. The encoding-mode-ppredicate and the get-encoding-modemethod can be used to detect the content encoding mode. However, it is worth to note that the HttpStreamobject is automatically sets with the proper encoding if it can be found in the response header.

Special client response
Certain response can sometime contains special status codes that require a specific treatment. This is the case when the response corresponds to a http redirection. In this case, the new uri must be fetched to get the desired response. The location-ppredicate returns true if the response corresponds to a http redirect and the get-locationmethod can be used to get the new location uri. If this situation arises, it is up to the implementation to decide what to do with the new uri. In most cases, a new request will be sent to the server.

Cookie object
The Cookieobject is a special object that can be used during a http session, to post data to the http client. The idea behind cookiesis to be able to maintain some state, during the user session for some time. A cookie is a name/valuepair and eventually an expiration time. By default, the cookie object are defined for one http client session, but this behavior can be changed.

Managing cookies
A cookie is created with a name/valuepair and eventually an expiration time. Such expiration time is called the maximum-ageand is automatically formatted by the object. With two arguments a session cookie is created. With a third argument as an integer, the constructor set the maximum age in seconds.

# create a cookie with name/value
const cookie (afnix:nwg:Cookie "cartid" "123456789")

The cookie implementation follows the recommendation of the RFC-2965 for http state management. The most important point to remember is the interpretation of the maximum age that differs from one cookie version to another. With version 1, which is the default, the maximum age is defined relatively in seconds, while it is absolute with version 0.The maximum age is set either at construction or with the set-max-agemethod. The set-max-agemethod sets the cookie life time in seconds, in reference to the current time. A negative value is always reset to -1 and defined a session cookie. A 0 value tells the http client to remove the cookie. The set-pathmethod defines the path for which this cookie apply.

Adding a cookie
Once the cookie is defined, the set-cookiemethod of the HttpResponseobject can be used to install the cookie. Combined with the writemethod, the cookie can be send to the http client.

STANDARD NETWORK WORKING GROUP REFERENCE

Uri
The Uriclass is a base object used to parse or build a uniform resource identifier as defined by RFC 3986. The URI can be built by specifying each component or by parsing a string. When a string is given in the constructor, the class parses the string and extract all components. The uri components are the scheme, the authority, the path, the query and the fragment. The class also takes care of the character escaping.

Predicate

: uri-p

Inheritance

: Object

Constructors

: Uri (none)
The Uriconstructor creates an empty uri object.

: Uri (String)
The Uriconstructor create a uri object by value. The string argument is the uri to parse at the object construction.

: Uri (String String Integer)
The Uriconstructor create a uri object by scheme host and port. The first argument is the uri scheme. The second argument is the uri host name. The third argument is the uri port. The uri base name can be reconstructed from this information.

Methods

: parse -> none (String)
The parsemethod reset the uri object, parse the string argument and fill the uri object with the result.

: get-scheme -> String (none)
The get-schememethod returns the scheme of the parsed uri object.

: get-authority -> String (none)
The get-authoritymethod returns the authority part of the parsed uri.

: get-path -> String (none)
The get-pathmethod returns the path of the parsed uri.

: get-path-target -> String (none)
The get-path-targetmethod returns the path target of the parsed uri. The path target is the last element of the uri path.

: get-query -> String (none)
The get-querymethod returns the complete query string of the parsed uri. Note that characters are not escaped when getting the string.

: get-fragment -> String (none)
The get-fragmentmethod returns the complete query string of the parsed uri.

: get-base -> String (none)
The get-basemethod returns the combined uri scheme and authority.

: get-rname -> String (none)
The get-rnamemethod returns the reference uri name with the combined uri scheme, authority and path all percent encoded.

: get-hname -> String (none)
The get-hnamemethod returns the combined uri scheme, authority and path.

: get-aname -> String (none)
The get-anamemethod returns the almost combined uri name with the scheme, authority, path and query.

: add-path -> Uri (String)
The add-pathmethod adds a path to the calling uri and returns a new uri with the new path added to the old one.

: get-href -> Uri (String)
The get-hrefmethod returns a new uri by eventually combining the string argument. If the string argument correspond to an uri, the corresponding uri is built. Otherwise, the string argument is considered as a path to be added to the current uri in order to build a new uri.

: get-system-path -> String (none)
The get-system-pathmethod returns the system path representation of the uri path. This function works only if the scheme if a file scheme.

: get-path-encoded -> String (none)
The get-path-encodedmethod returns the uri in the encoded form. Normally the get-pathremoves the percent-encoded characters which might not be appropriate with some protocol such like the http protocol. The get-path-encodedreturns the original path. Note that getting the path with getpathand doing a percent coding might result in a different result since the internal representation uses normalized string.

: get-host -> String (none)
The get-hostmethod returns the authority or path host name if any can be found with respect to the scheme. With a ftp, http or https scheme, the host is extracted from the authority. With a mailto scheme, the host is extracted from the path.

: get-port -> Integer (none)
The get-portmethod returns the authority port if any can be found with respect to the scheme.

UriQuery
The UriQueryclass is a simple class that parses a uri query string and build property list. during the parsing process, a special transliteration process is done as specified by RFC 3986. This class is primarily used with cgiscripts. Note that the string to parse is exactly the one produced by the get-querymethod of the Uriclass.

Predicate

: uri-query-p

Inheritance

: Plist

Constructors

: UriQuery (none)
The UriQueryconstructor creates an empty uri query object.

: UriQuery (String)
The UriQueryconstructor create a uri object by value. The string argument is the uri query string to parse at the object construction. The query string is the one obtained from the get-querymethod of the Uriclass.

Methods

: parse -> none (String)
The parsemethod reset the uri query object, parses the string argument and fill the property list object with the result.

: get-query -> String (none)
The get-querymethod returns the original query string.

UriPath
The UriPathclass is a class designed for the management of file system path associated with a uri. Typically, this class will be used with a http server or client when an association between a uri and a file name needs to be made. The general operation principle is to associate a path with a uri authority. The uri path is then concatanated to produce a new path. If the uri path is empty, it can be eventually replaced by a file name, known as the diretory index in the http terminology.

Predicate

: uri-path-p

Inheritance

: Object

Constructors

: UriPath (none)
The UriPathconstructor creates an empty uri path object.

: UriPath (String)
The UriPathconstructor create a uri object by root path. The string argument is the uri root path.

: UriPath (String String)
The UriPathconstructor create a uri object by root and index. The first string argument is the uri root path and the second string argument is the directory index path.

: UriPath (String String String)
The UriPathconstructor create a uri object by root, index and authority. The first string argument is the uri root path, the second string argument is the directory index path and the third argument is the authority.

Methods

: get-root -> String (none)
The get-rootmethod returns the root path.

: get-index -> String (none)
The get-indexmethod returns the index path.

: get-authority -> String (none)
The get-authoritymethod returns the uri authority.

: map-request-uri -> String (none)
The map-request-urimap a request uri into a system path. The string argument is the request uri. The request uri must be an absolute path. The result string is the system path build with the root path.

: normalize -> String (none)
The normalizemethod build a system from a request path. The request path is associated with the root path and then normalized to produce a complete system path.

HttpProto
The HttpProtoclass is a base class that ease the deployment of the http protocol. The base class is built with a property list which is used to define the message header. The class also defines the write methods which are used to write a message either on an output stream or into a buffer.

Predicate

: http-proto-p

Inheritance

: Object

Methods

: reset -> none (none)
The resetmethod resets the http protocol object by clearing the protocol version and header.

: parse -> none (none)
The parsemethod parse the input stream bound to the http protocol. In order to operate, an input stream must be associated with the protocol object or an exception is raised. After a stream has been parsed, the protocol version and the header are set.

: write -> none (none|OutputStream|Buffer)
The writemethod formats and writes the http protocol object to an output stream or a buffer. Without argument, the default output stream is used. With an argument, an output stream or a buffer object can be used.

: header-length -> Integer (none)
The header-lengthmethod returns the number of properties in the header.

: header-exists-p -> Boolean (String)
The header-exists-ppredicate returns true if the property exists in the header. The string argument is the property name.

: header-set -> none (String Literal)
The header-setmethod sets a new property to the http header. The first argument is the property name. The second argument is a literal object which is internally converted to a string.

: header-get -> Property (Integer)
The header-getmethod returns a property object by index.

: header-map -> String (String)
The header-mapmethod returns a property value by name. The string argument is the property name.

: header-find -> Property (String)
The header-findmethod returns a property object by name. The string argument is the property name. If the property is not found, the nil object is returned.

: header-lookup -> Property (String)
The header-lookupmethod returns a property object by name. The string argument is the property name. If the property is not found, an exception is raised.

: header-plist -> Plist (none)
The header-plistmethod returns the header in the form of a property list.

: content-length-p -> Boolean (none)
The content-length-ppredicate returns true if the content length is defined in the protocol header.

: get-content-length -> Integer (none)
The get-content-lengthmethod returns the content length defined in the protocol header. If the content length is not defined in the header, the null value is returned.

: media-type-p -> Boolean (none)
The media-type-ppredicate returns true if the content type is defined in the protocol header.

: get-media-type -> String (none)
The get-media-typemethod returns the media type defined in the protocol header. If the media type is not defined in the header, the default media type is returned.

: encoding-mode-p -> Boolean (none)
The encoding-mode-ppredicate returns true if the encoding mode is defined in the protocol header.

: get-encoding-mode -> String (none)
The get-encoding-modemethod returns the protocol encoding mode. If the encoding mode is not defined in the protocol header, the default encoding mode is returned.

HttpRequest
The HttpRequestclass is a base class designed to handle a http request. The class operates with the protocol version 1.1 as defined by RFC 2616. For a server request, the request is built by reading an input stream and setting the request command with its associated header. For a client request, the request is formatted with a request command and a eventually a uri. In both cases, the header is filled automatically depending on the request side.

Predicate

: http-request-p

Inheritance

: HttpProto

Constructors

: HttpRequest (none)
The HttpRequestconstructor creates a default http request. By default, the request object is built with the GETmethod and the request uri set to the root value.

: HttpRequest (String)
The HttpRequestconstructor creates a http request object with a specific command. By default, the request uri is set to root, except for the OPTIONSmethod

: HttpRequest (Uri)
The HttpRequestconstructor creates a http request object with a uri. The default request method is GET.

: HttpRequest (InputStream)
The HttpRequestconstructor creates a http request object with a specific input stream. At construction, the request header is cleared and the input stream is bound to the object.

: HttpRequest (String String)
The HttpRequestconstructor creates a http request object with a specific method and a uri name. The first string argument is the request method to use. The second string argument is the uri attached to the command. Note that the term urishould be understood as a request uri.

: HttpRequest (String Uri)
The HttpRequestconstructor creates a http request object with a specific method and a uri. The first string argument is the request method to use. The second argument is the uri attached to the method.

Methods

: set-method -> none (String)
The set-methodmethod sets the request method. This method does not check that the command is a valid HTTP method and thus leaves plenty of room for server development. As a matter of fact, RFC 2616 does not prohibit the existence of such extension.

: get-method -> String (none)
The get-methodmethod returns the request method string.

: set-uri -> none (String)
The set-urimethod sets the request uri. The argument string does not have to be a valid uri string since some commands might accept special string such like "*" to indicate all applicable uri.

: get-uri -> String (none)
The get-urimethod returns the request uri string.

HttpResponse
The HttpResponseclass is a base class designed to handle a http response. The class operates with the protocol version 1.1 as defined by RFC 2616. For a client response, the response is built by reading an input stream and setting the response status code with its associated header. For a server response, the response is formatted with a response status and additional header information. In both cases, the header is filled automatically depending on the response side. On the other hand, trying to set some header with an input stream bound to the response object might render the response object unusable.

Predicate

: http-response-p

Inheritance

: HttpProto

Constructors

: HttpResponse (none)
The HttpResponseconstructor creates a default http response object. The response is marked valid with a default text/plainmedia type.

: HttpResponse (Integer)
The HttpResponseconstructor creates a http response object with a status code. The response code is associated with the default text/plainmedia type.

: HttpResponse (InputStream)
The HttpResponseconstructor creates a http response object with a specific input stream. At construction, the response header is cleared and the input stream is bound to the object.

: HttpResponse (Integer String)
The HttpResponseconstructor creates a http response object with a status code and a media type. The first argument is the status code. The second argument is the associated media type.

Methods

: set-status-code -> none (Integer)
The set-status-codemethod sets the response status code.

: get-status-code -> Integer (none)
The get-status-codemethod returns the response status code.

: map-status-code -> String (none)
The map-status-codemethod returns a string representation of the response status code.

: status-ok-p -> Boolean (none)
The status-ok-ppredicate returns true if the response status code is valid (aka status 200).

: status-error-p -> Boolean (none)
The status-error-ppredicate returns true if the response status code is an error code.

: location-p -> Boolean (none)
The location-ppredicate returns true is the response status code indicates that a request should be made at another location. The location can be found with the get-locationmethod.

: get-location -> String (none)
The get-locationmethod returns the location uri found in the response header. This method is equivalent to a header query.

: set-location -> none (String)
The set-locationmethod set the redirect location in the response header. The string argument is the location uri.

: set-cookie -> none (Cookie)
The set-cookiemethod sets a cookie object to the http header. The cookie version is properly handled by the method.

Cookie
The Cookieclass is a special class designed to handle cookie setting within a http transaction. A cookie is name/valuepair that is set by the server and stored by the http client. Further connection with the client will result with the cookie value transmitted by the client to the server. A cookie has various parameters that controls its existence and behavior. The most important one is the cookie maximum agethat is defined in seconds. A null value tells the client to discard the cookie. A cookie without maximum age is valid only during the http client session. A cookie can be added to the HttpReplyobject with the set-cookiemethod. A cookie can be constructed with a name/valuepair. An optional third argument is the maximum age. The default cookie version is 1 as specified by RFC 2965. With a version 1, the maximum age is interpreted as the number of seconds before the cookie expires. With version 0, the maximum age is the absolute time.

Predicate

: cookie-p

Inheritance

: Object

Constructors

: Cookie (String String)
The Cookieconstructor creates a cookie with a name value pair. The first argument is the cookie name. The second argument is the cookie value.

: Cookie (String String Integer)
The Cookieconstructor creates a cookie with a name value pair and a maximum age. The first argument is the cookie name. The second argument is the cookie value. The third argument is the cookie maximum age.

Methods

: get-version -> Integer (none)
The get-versionmethod returns the cookie version.

: set-version -> none (Integer)
The set-versionmethod sets the cookie version. The version number can only be 0 or 1.

: get-name -> String (none)
The get-namemethod returns the cookie name. This is the name store on the http client.

: set-name -> none (String)
The set-namemethod sets the cookie name. This is the name store on the http client.

: get-value -> String (none)
The get-valuemethod returns the cookie value. This is the value stored on the http client bounded by the cookie name.

: set-value -> none (String)
The set-valuemethod sets the cookie value. This is the value store on the http client bounded by the cookie name.

: get-maximum-age -> Integer (none)
The get-maximum-agemethod returns the cookie maximum age. The default value is -1, that is, no maximum age is set and the cookie is valid only for the http client session.

: set-maximum-age -> none (Integer)
The set-maximum-agemethod sets the cookie maximum age. A negative value is reset to -1. A 0 value tells the http client to discard the cookie. A positive value tells the http client to store the cookie for the remaining seconds.

: get-path -> String (none)
The get-pathmethod returns the cookie path value. The path determines for which http request the cookie is valid.

: set-path -> none (String)
The set-pathmethod sets the cookie path value. The path determines for which http request the cookie is valid.

: get-domain -> String (none)
The get-domainmethod returns the cookie domain value.

: set-domain -> none (String)
The set-domainmethod sets the cookie domain value. It is string recommended to use the originator domain name since many http client can reject cookie those domain name does not match the originator name.

: get-port -> Integer (none)
The get-portmethod returns the cookie port number.

: set-port -> none (Integer)
The set-portmethod sets the cookie port number. This value is not used with a cookie version 0.

: get-comment -> String (none)
The get-commentmethod returns the cookie comment value.

: set-comment -> none (String)
The set-commentmethod sets the cookie comment value.

: get-comment-url -> String (none)
The get-comment-urlmethod returns the cookie comment url value.

: set-comment-url -> none (String)
The set-comment-urlmethod sets the cookie comment url value. This value is not used with cookie version 0.

: get-discard -> Boolean (none)
The get-discardmethod returns the cookie discard flag.

: set-discard -> none (Boolean)
The set-discardmethod sets the cookie discard flag. The discard flag the tells the user agent to destroy the cookie when it terminates. This value is not used with cookie version 0.

: get-secure -> Boolean (none)
The get-securemethod returns the cookie secure flag.

: set-secure -> none (Boolean)
The set-securemethod sets the cookie secure flag. When a cookie is secured, it is only returned by the http client if a connection has been secured (i.e use https).

: to-string -> String (none)
The to-stringmethod returns a string formatted for the http reply header. Normally this method should not be called since the set-cookiemethod of the httpReplytakes care of such thing.

Functions

: mime-extension-p -> Boolean (String)
The mime-extension-ppredicates returns true if a media type extension - mime extension - is defined. Most of the time, media type extension can be seen as a file extension.

: mime-value-p -> Boolean (String)
The mime-value-ppredicates returns true if a media type - mime value - is defined.

: extension-to-mime -> String (String [Boolean])
The extension-to-mimefunction converts a media type extension into a media type. In the first form, without a second argument, if the media type extension does not exist, an exception is raised. In the second form, with the second argument set to true, if the media type extension does not exist, the default media type is returned. If the flag is set to false, an exception is raised like the first form.

: normalize-uri-name -> String (String)
The normalize-uri-namefunction normalizes the string argument by adding a uri scheme if missing in the original string. If the function detects that the name starts with a host name, the "http" scheme is added. If the function detects that the string starts with a path, the "file" scheme is added. otherwise, the name argument is left untouched.

: system-uri-name -> String (String)
The system-uri-namefunction normalizes the string argument by prioritizing the system name. The function attempts to find a file that match the string argument and eventually build a uri file scheme. If the file is not fond, the normalization process occurs with the normalize-uri-namefunction.

: path-uri-name -> String (String)
The path-uri-namefunction normalizes the string argument by extracting a path associated with the uri string. If the string is a valid uri string, the path is the uri path component. If the uri path is empty, it is normalized to a /. If the string argument is not a uri string, the string is assumed to be a partial uri and both query and fragment parts are removed if present.

STANDARD NETWORK WORKING GROUP MODULE

STANDARD NETWORK WORKING GROUP REFERENCE

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