49.2. Working with the full request URI

Abstract

The request URI contains a significant amount of information. Most of this information can be accessed using method parameters as described in Section 44.2.2, “Injecting data from a request URI”, however using parameters forces certain constraints on how the URI is processed. Using parameters to access the segments of a URI also does not provide a resource access to the full request URI.
You can provide access to the complete request URI by injecting the URI context into a resource. The URI is provided as a UriInfo object. The UriInfo interface provides functions for decomposing the URI in a number of ways. It can also provide the URI as a UriBuilder object that allows you to construct URIs to return to clients.

49.2.1. Injecting the URI information

Overview

When a class field or method parameter that is a UriInfo object is decorated with the @Context annotation, the URI context for the current request is injected into the UriInfo object.

Example

Example 49.1, “Injecting the URI context into a class field” shows a class with a field populated by injecting the URI context.

Example 49.1. Injecting the URI context into a class field

import javax.ws.rs.core.Context;
import javax.ws.rs.core.UriInfo;
import javax.ws.rs.Path;
...
@Path("/monstersforhire/")
public class MonsterService
{
  @Context
  UriInfo requestURI;
  ...
}

49.2.2. Working with the URI

Overview

One of the main advantages of using the URI context is that it provides access to the base URI of the service and the path segment of the URI for the selected resource. This information can be useful for a number of purposes such as making processing decisions based on the URI or calculating URIs to return as part of the response. For example if the base URI of the request contains a .com extension the service may decide to use US dollars and if the base URI contains a .co.uk extension is may decide to us British Pounds.
The UriInfo interface provides methods for accessing the parts of the URI:
  • the base URI
  • the resource path
  • the full URI

Getting the Base URI

The base URI is the root URI on which the service is published. It does not contain any portion of the URI specified in any of the service's @Path annotations. For example if a service implementing the resource defined in Example 44.5, “Disabling URI decoding” were published to http://fusesource.org and a request was made on http://fusesource.org/montersforhire/nightstalker?12 the base URI would be http://fusesource.org.
Table 49.2, “Methods for accessing a resource's base URI” describes the methods that return the base URI.

Table 49.2. Methods for accessing a resource's base URI

MethodDesription
URI getBaseUri(); Returns the service's base URI as a URI object.
UriBuilder getBaseUriBuilder(); Returns the base URI as a javax.ws.rs.core.UriBuilder object. The UriBuilder class is useful for creating URIs for other resources implemented by the service.

Getting the path

The path portion of the request URI is the portion of the URI that was used to select the current resource. It does not include the base URI, but does include any URI template variable and matrix parameters included in the URI.
The value of the path depends on the resource selected. For example, the paths for the resources defined in Example 49.2, “Getting a resource's path” would be:
  • rootPath — /monstersforhire/
  • getterPath — /mostersforhire/nightstalker
    The GET request was made on /monstersforhire/nightstalker.
  • putterPath — /mostersforhire/911
    The PUT request was made on /monstersforhire/911.

Example 49.2. Getting a resource's path

@Path("/monstersforhire/")
public class MonsterService
{
  @Context
  UriInfo rootUri;

  ...

  @GET
  public List<Monster> getMonsters(@Context UriInfo getUri)
  {
    String rootPath = rootUri.getPath();
    ...
  }

  @GET
  @Path("/{type}")
  public Monster getMonster(@PathParam("type") String type,
                            @Context UriInfo getUri)
  {
    String getterPath = getUri.getPath();
    ...
  }

  @PUT
  @Path("/{id}")
  public void addMonster(@Encoded @PathParam("type") String type,
                         @Context UriInfo putUri)
  {
    String putterPath = putUri.getPath();
    ...
  }
  ...
}
Table 49.3, “Methods for accessing a resource's path” describes the methods that return the resource path.

Table 49.3. Methods for accessing a resource's path

MethodDesription
String getPath(); Returns the resource's path as a decoded URI.
String getPath(boolean decode); Returns the resource's path. Specifying false disables URI decoding.
List<PathSegment> getPathSegments();
Returns the decoded path as a list of javax.ws.rs.core.PathSegment objects. Each portion of the path, including matrix parameters, is placed into a unique entry in the list.
For example the resource path box/round#tall would result in a list with three entries: box, round, and tall.
List<PathSegment> getPathSegments(boolean decode);
Returns the path as a list of javax.ws.rs.core.PathSegment objects. Each portion of the path, including matrix parameters, is placed into a unique entry in the list. Specifying false disables URI decoding.
For example the resource path box#tall/round would result in a list with three entries: box, tall, and round.

Getting the full request URI

Table 49.4, “Methods for accessing the full request URI” describes the methods that return the full request URI. You have the option of returning the request URI or the absolute path of the resource. The difference is that the request URI includes the any query parameters appended to the URI and the absolute path does not include the query parameters.

Table 49.4. Methods for accessing the full request URI

MethodDesription
URI getRequestUri(); Returns the complete request URI, including query parameters and matrix parameters, as a java.net.URI object.
UriBuilder getRequestUriBuilder(); Returns the complete request URI, including query parameters and matrix parameters, as a javax.ws.rs.UriBuilder object. The UriBuilder class is useful for creating URIs for other resources implemented by the service.
URI getAbsolutePath(); Returns the complete request URI, including matrix parameters, as a java.net.URI object. The absolute path does not include query parameters.
UriBuilder getAbsolutePathBuilder(); Returns the complete request URI, including matrix parameters, as a javax.ws.rs.UriBuilder object. The absolute path does not include query parameters.
For a request made using the URI http://fusesource.org/montersforhire/nightstalker?12, the getRequestUri() methods would return http://fusesource.org/montersforhire/nightstalker?12. The getAbsolutePath() method would return http://fusesource.org/montersforhire/nightstalker.

49.2.3. Getting the value of URI template variables

Overview

As described in the section called “Setting the path”, resource paths can contain variable segments that are bound to values dynamically. Often these variable path segments are used as parameters to a resource method as described in the section called “Getting data from the URI's path”. You can, however, also access them through the URI context.

Methods for getting the path parameters

The UriInfo interface provides two methods, shown in Example 49.3, “Methods for returning path parameters from the URI context”, that return a list of the path parameters.

Example 49.3. Methods for returning path parameters from the URI context

MultivaluedMap<java.lang.String, java.lang.String> getPathParameters();
MultivaluedMap<java.lang.String, java.lang.String> getPathParameters(boolean decode);
The getPathParameters() method that does not take any parameters automatically decodes the path parameters. If you want to disable URI decoding use getPathParameters(false).
The values are stored in the map using their template identifiers as keys. For example if the URI template for the resource is /{color}/box/{note} the returned map will have two entries with the keys color and note.

Example

Example 49.4, “Extracting path parameters from the URI context” shows code for retrieving the path parameters using the URI context.

Example 49.4. Extracting path parameters from the URI context

import javax.ws.rs.Path;
import javax.ws.rs.Get;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.UriInfo;
import javax.ws.rs.core.MultivaluedMap;

@Path("/monstersforhire/")
public class MonsterService

  @GET
  @Path("/{type}/{size}")
  public Monster getMonster(@Context UriInfo uri)
  {
    MultivaluedMap paramMap = uri.getPathParameters();
    String type = paramMap.getFirst("type");
    String size = paramMap.getFirst("size");
  }
}