Difference between revisions of "REST"

From BaseX Documentation
Jump to navigation Jump to search
m (Text replacement - "8984" to "8080")
Tags: Mobile web edit Mobile edit
(16 intermediate revisions by 2 users not shown)
Line 2: Line 2:
  
 
BaseX offers a RESTful API for accessing database resources via URLs.
 
BaseX offers a RESTful API for accessing database resources via URLs.
REST ([http://en.wikipedia.org/wiki/Representational_State_Transfer REpresentational State Transfer])
+
REST ([https://en.wikipedia.org/wiki/Representational_State_Transfer REpresentational State Transfer])
 
facilitates a simple and fast access to databases through HTTP. The HTTP methods
 
facilitates a simple and fast access to databases through HTTP. The HTTP methods
 
GET, PUT, DELETE, and POST can be used to interact with the database.
 
GET, PUT, DELETE, and POST can be used to interact with the database.
Line 8: Line 8:
 
=Usage=
 
=Usage=
  
By default, REST services are available at {{Code|http://localhost:8984/rest/}}. If no default credentials are specified in the URL or when starting the web application, they will be requested by the client ([[Web Application#User Management|see further]]).
+
By default, REST services are available at {{Code|http://localhost:8080/rest/}}. If no default credentials are specified in the URL or when starting the web application, they will be requested by the client ([[Web Application#User Management|see further]]).
  
 
A web browser can be used to perform simple GET-based REST requests and display the response. Some alternatives for using REST are listed in the [[#Usage Examples|Usage Examples]].
 
A web browser can be used to perform simple GET-based REST requests and display the response. Some alternatives for using REST are listed in the [[#Usage Examples|Usage Examples]].
 +
 +
With {{Announce|BaseX 10}}, results in the {{Code|rest}} namespace will be returned unprefixed:
 +
 +
<syntaxhighlight lang="xml">
 +
<!-- before -->
 +
<rest:databases xmlns:rest="http://basex.org/rest"/>
 +
 +
<!-- before -->
 +
<databases xmlns="http://basex.org/rest"/>
 +
</syntaxhighlight>
  
 
=URL Architecture=
 
=URL Architecture=
 +
 +
A request to the root URL returns all available databases:
 
   
 
   
The root URL lists all available databases. The following examples assume that
+
:<code>http://localhost:8080/rest</code>
you have created a database instance from the [http://files.basex.org/xml/factbook.xml factbook.xml] document:
 
 
   
 
   
:<code>http://localhost:8984/rest</code>
+
<syntaxhighlight lang="xml">
+
<databases xmlns="http://basex.org/rest">
<pre class="brush:xml">  
+
   <database resources="25742" size="43813599">articles</database>
<rest:databases resources="1" xmlns:rest="http://basex.org/rest">
+
  ...
   <rest:database resources="1" size="1813599">factbook</rest:database>
+
</databases>
</rest:databases>
+
</syntaxhighlight>
</pre>  
+
 
 +
The resources of a database (directories, resource metadata) are listed if a database and an optional directory path is specified:
  
The resources of a database can be listed by specifying the database, and potential sub directories, in the URL.
+
:<code>http://localhost:8080/rest/articles</code>
In the given example, a single XML document is stored in the ''factbook'' database:
 
  
:<code>http://localhost:8984/rest/factbook</code>
+
<syntaxhighlight lang="xml">
 +
<database name="articles" xmlns="http://basex.org/rest">
 +
  <dir>binaries</dir>
 +
  <resource type="xml" content-type="application/xml" size="77192">1973-02-08-xltp325.xml</resource>
 +
  ...
 +
</database>
 +
</syntaxhighlight>
  
<pre class="brush:xml">
+
The {{Code|dir}} elements were introduced with {{Announce|Version 10}}. Before, information on all resources was listed that were located in the specified path or any of its subdirectories.
<rest:database name="factbook" resources="1" xmlns:rest="http://basex.org/rest">
 
  <rest:resource type="xml" content-type="application/xml" size="77192">factbook.xml</rest:resource>
 
</rest:database>
 
</pre>
 
 
The contents of a database can be retrieved by directly addressing the resource:
 
 
   
 
   
:<code>http://localhost:8984/rest/factbook/factbook.xml</code>
+
If the path to a single resource is specified, the resource itself will be returned:
 
   
 
   
If a resource is not found, an HTTP response will be generated with <code>404</code> as status code.
+
:<code>http://localhost:8080/rest/articles/1973-02-08-xltp325.xml</code>
 
   
 
   
 
==Parameters==
 
==Parameters==
Line 60: Line 71:
 
Additionally, the following '''operations''' can be specified:
 
Additionally, the following '''operations''' can be specified:
  
* {{Code|query}}: Evaluate an XQuery expression. If a database or database path is specified in the URL, it is used as initial query context.
+
* {{Code|query}}: Evaluate an XQuery expression. If a database or database path is specified in the URL, it is set as query context.
 
* {{Code|command}}: Execute a single [[Commands|database command]].
 
* {{Code|command}}: Execute a single [[Commands|database command]].
* {{Code|run}}: Evaluate an XQuery file or command script located on the server. The file path is resolved against the directory specified by <code>[[Options#WEBPATH|RESTPATH]]</code> (before, it was resolved against <code>[[Options#WEBPATH|WEBPATH]]</code>).
+
* {{Code|run}}: Evaluate an XQuery file or command script located on the server. The file path is resolved against the directory specified by {{Option|RESTPATH}} (before, it was resolved against {{Option|WEBPATH}}). Similar to {{Code|query}}, a database or database path is set as context.
  
 
; Examples
 
; Examples
  
* Lists all resources found in the '''tmp''' path of the ''factbook'' database:<br/><code>http://localhost:8984/rest/factbook/tmp</code>
+
* Lists all resources found in the '''tmp''' path of the ''factbook'' database:<br/><code>http://localhost:8080/rest/factbook/tmp</code>
 +
 
 +
* Returns the number of documents in a database:<br/><code>http://localhost:8080/rest/database?query=count(.)</code>
  
* Serializes a document as JSONML:<br/><code>http://localhost:8984/rest/factbook/factbook.xml?method=json&json=format=jsonml</code>
+
* Serializes a document as JSONML:<br/><code>http://localhost:8080/rest/factbook/factbook.xml?method=json&json=format=jsonml</code>
  
* <code>US-ASCII</code> is chosen as output encoding, and the query <code>eval.xq</code> is evaluated:<br/><code>http://localhost:8984/rest?run=eval.xq&encoding=US-ASCII</code>
+
* <code>US-ASCII</code> is chosen as output encoding, and the query <code>eval.xq</code> is evaluated:<br/><code>http://localhost:8080/rest?run=eval.xq&encoding=US-ASCII</code>
  
* The next URL lists all database users that are known to BaseX:<br/><code>http://localhost:8984/rest?command=show+users</code>
+
* The next URL lists all database users that are known to BaseX:<br/><code>http://localhost:8080/rest?command=show+users</code>
  
 
==POST Method==
 
==POST Method==
  
The body of a POST request is interpreted as XML fragment, which specifies the
+
The body of a POST request is interpreted as XML fragment, which specifies the operation to perform.
operation to perform. The body must conform to a given [[REST: POST Schema|XML Schema]].
+
The name of the root element determines how the body will be evaluated:
 +
 
 +
* {{Code|commands}}: Run [[Commands#Command Scripts|Command Script]]
 +
* {{Code|query}}: Execute XQuery expression
 +
* {{Code|run}}: Run server-side file (query or command script)
 +
* {{Code|command}}: Execute single command
 +
 
 +
The root element may be bound to the optional REST namespace. Existing command scripts can be sent to the server without any modifications:
 +
 
 +
* Create an empty database and return database information:
 +
<syntaxhighlight lang="xml">
 +
<commands>
 +
  <create-db name='db'/>
 +
  <info-db/>
 +
</commands>
 +
</syntaxhighlight>
 +
 
 +
For the other commands, the following child elements are supported:
 +
 
 +
{| class="wikitable"
 +
|-
 +
! Name
 +
! Description
 +
|-
 +
| {{Code|text}}
 +
| Required; contains the query string, command string, or file to be run
 +
|-
 +
| {{Code|parameter}}
 +
| Serialization parameter (with {{Code|@name}} and {{Code|@value}} attributes)
 +
|-
 +
| {{Code|option}}
 +
| Database option (with {{Code|@name}} and {{Code|@value}} attributes)
 +
|-
 +
| {{Code|variable}}
 +
| Variable bindings
 +
|-
 +
| {{Code|context}}
 +
| Initial context item
 +
|}
  
 
; Examples
 
; Examples
  
* The following query returns the first five city names of the <b>factbook</b> database:  
+
* Return the first five city names of the <b>factbook</b> database:
<pre class="brush:xml">
+
<syntaxhighlight lang="xml">
<query xmlns="http://basex.org/rest">
+
<rest xmlns="http://basex.org/rest">
   <text><![CDATA[ (//city/name)[position() <= 5] ]]></text>
+
   <rest><![CDATA[ (//city/name)[position() <= 5] ]]></text>
</query>
+
</rest>
</pre>
+
</syntaxhighlight>
  
* The second query returns the string lengths of all text nodes, which are found in the node that has been specified as initial context node:
+
* Return string lengths of all text nodes that are found in the node that has been specified as initial context node:
<pre class="brush:xml">
+
<syntaxhighlight lang="xml">
<rest:query xmlns:rest="http://basex.org/rest">
+
<query>
   <rest:text>for $i in .//text() return string-length($i)</rest:text>
+
   <text>for $i in .//text() return string-length($i)</text>
   <rest:context>
+
   <context>
 
     <xml>
 
     <xml>
 
       <text>Hello</text>
 
       <text>Hello</text>
 
       <text>World</text>
 
       <text>World</text>
 
     </xml>
 
     </xml>
   </rest:context>
+
   </context>
</rest:query>
+
</query>
</pre>
+
</syntaxhighlight>
  
* The following request returns the registered database users encoded in <code>ISO-8859-1</code>:
+
* Return the registered database users encoded in <code>ISO-8859-1</code>:
<pre class="brush:xml">
+
<syntaxhighlight lang="xml">
<command xmlns="http://basex.org/rest">
+
<command>
 
   <text>show users</text>
 
   <text>show users</text>
 
   <parameter name='encoding' value='ISO-8859-1'/>
 
   <parameter name='encoding' value='ISO-8859-1'/>
 
</command>
 
</command>
</pre>
+
</syntaxhighlight>
  
* This example creates a new database from the specified input and retains all whitespaces:
+
* Create a new database from the specified input and preserve all whitespaces:
<pre class="brush:xml">
+
<syntaxhighlight lang="xml">
<command xmlns="http://basex.org/rest">
+
<command>
 
   <text>create db test http://files.basex.org/xml/xmark.xml</text>
 
   <text>create db test http://files.basex.org/xml/xmark.xml</text>
 
   <option name='chop' value='false'/>
 
   <option name='chop' value='false'/>
 
</command>
 
</command>
</pre>
+
</syntaxhighlight>
  
* The last request runs a query <code>query.xq</code> located in the directory specified by <code>[[Options#WEBPATH|WEBPATH]]</code>:
+
* Bind value to the {{Code|$person}} variable and run query <code>find-person.xq</code>, which must be located in the directory specified by {{Option|WEBPATH}}:
<pre class="brush:xml">
+
<syntaxhighlight lang="xml">
<run xmlns="http://basex.org/rest">
+
<run>
   <text>query.xq</text>
+
  <variable name='person' value='Johannes Müller'/>
 +
   <text>find-person.xq</text>
 
</run>
 
</run>
</pre>
+
</syntaxhighlight>
  
 
==PUT Method==
 
==PUT Method==
Line 146: Line 198:
 
; Examples
 
; Examples
  
* A new database with the name <b>XMark</b> is created. If XML input is sent in the HTTP body, the resulting database resource will be called <b>XMark.xml</b>:<br/><code><nowiki>http://localhost:8984/rest/XMark</nowiki></code>
+
* A new database with the name <b>XMark</b> is created. If XML input is sent in the HTTP body, the resulting database resource will be called <b>XMark.xml</b>:<br/><code><nowiki>http://localhost:8080/rest/XMark</nowiki></code>
* A new database is created, and no whitespaces will be removed from the passed on XML input:<br/><code><nowiki>http://localhost:8984/rest/XMark?chop=false</nowiki></code>
+
* A new database is created, and no whitespaces will be removed from the passed on XML input:<br/><code><nowiki>http://localhost:8080/rest/XMark?chop=false</nowiki></code>
* The contents of the HTTP body will be taken as input for the document <b>one.xml</b>, which will be stored in the <b>XMark</b> database:<br/><code><nowiki>http://localhost:8984/rest/XMark/one.xml</nowiki></code>
+
* The contents of the HTTP body will be taken as input for the document <b>one.xml</b>, which will be stored in the <b>XMark</b> database:<br/><code><nowiki>http://localhost:8080/rest/XMark/one.xml</nowiki></code>
  
 
An HTTP response with status code <code>201</code> (CREATED)
 
An HTTP response with status code <code>201</code> (CREATED)
Line 163: Line 215:
  
 
; Example
 
; Example
* The <b>factbook</b> database is deleted:<br/><code><nowiki>http://localhost:8984/rest/factbook</nowiki></code>
+
* The <b>factbook</b> database is deleted:<br/><code><nowiki>http://localhost:8080/rest/factbook</nowiki></code>
* All resources of the <b>XMark</b> database are deleted that reside in the <b>tmp</b> path:<br/><code><nowiki>http://localhost:8984/rest/XMark/tmp/</nowiki></code>
+
* All resources of the <b>XMark</b> database are deleted that reside in the <b>tmp</b> path:<br/><code><nowiki>http://localhost:8080/rest/XMark/tmp/</nowiki></code>
 
   
 
   
 
The HTTP status code <code>404</code> is returned if no database is specified.
 
The HTTP status code <code>404</code> is returned if no database is specified.
Line 177: Line 229:
 
; Example
 
; Example
  
* The following request assigns two variables to a server-side query file <code>mult.xq</code> placed in the HTTP directory:<br/><code>http://localhost:8984/rest?run=mult.xq&$a=21&$b=2</code>
+
* The following request assigns two variables to a server-side query file <code>mult.xq</code> placed in the HTTP directory:<br/><code>http://localhost:8080/rest?run=mult.xq&$a=21&$b=2</code>
<pre class="brush:xquery">
+
<syntaxhighlight lang="xquery">
 
(: XQuery file: mult.xq :)
 
(: XQuery file: mult.xq :)
 
declare variable $a as xs:integer external;
 
declare variable $a as xs:integer external;
 
declare variable $b as xs:integer external;
 
declare variable $b as xs:integer external;
 
<mult>{ $a * $b }</mult>
 
<mult>{ $a * $b }</mult>
</pre>
+
</syntaxhighlight>
  
 
The dollar sign can be omitted as long as the variable name does not equal a parameter keyword (e.g.: <code>method</code>).
 
The dollar sign can be omitted as long as the variable name does not equal a parameter keyword (e.g.: <code>method</code>).
Line 191: Line 243:
 
If <code>query</code> or <code>run</code> is used as operation, external variables can be specified via the <code><variable/></code> element:
 
If <code>query</code> or <code>run</code> is used as operation, external variables can be specified via the <code><variable/></code> element:
  
<pre class="brush:xml">
+
<syntaxhighlight lang="xml">
 
<query xmlns="http://basex.org/rest">
 
<query xmlns="http://basex.org/rest">
 
   <text><![CDATA[
 
   <text><![CDATA[
     declare variable $x as xs:integer external;
+
     declare variable $a as xs:integer external;
     declare variable $y as xs:integer external;
+
     declare variable $b as xs:integer external;
 
     <mult>{ $a * $b }</mult>
 
     <mult>{ $a * $b }</mult>
 
   ]]></text>
 
   ]]></text>
Line 201: Line 253:
 
   <variable name="b" value="2"/>
 
   <variable name="b" value="2"/>
 
</query>
 
</query>
</pre>
+
</syntaxhighlight>
  
 
=Response=
 
=Response=
Line 225: Line 277:
 
The following three example requests all return <code>&lt;a/&gt;</code> with <code>application/xml</code> as content-type:
 
The following three example requests all return <code>&lt;a/&gt;</code> with <code>application/xml</code> as content-type:
  
:<code>http://localhost:8984/rest?query=%3Ca/%3E</code><br/><code>http://localhost:8984/rest?query=%3Ca/%3E&method=xml</code><br/><code>http://localhost:8984/rest?query=%3Ca/%3E&media-type=application/xml</code>
+
:<code>http://localhost:8080/rest?query=%3Ca/%3E</code><br/><code>http://localhost:8080/rest?query=%3Ca/%3E&method=xml</code><br/><code>http://localhost:8080/rest?query=%3Ca/%3E&media-type=application/xml</code>
  
 
=Usage Examples=
 
=Usage Examples=
Line 243: Line 295:
 
<code>org.basex.util.Base64</code> can be used for that purpose:
 
<code>org.basex.util.Base64</code> can be used for that purpose:
  
<pre class="brush:java">
+
<syntaxhighlight lang="java">
 
import java.net.*;
 
import java.net.*;
 
import org.basex.util.*;
 
import org.basex.util.*;
Line 250: Line 302:
 
   public static void main(String[] args) throws Exception {
 
   public static void main(String[] args) throws Exception {
 
     // The java URL connection to the resource.  
 
     // The java URL connection to the resource.  
     URL url = new URL("http://localhost:8984/rest/factbook");  
+
     URL url = new URL("http://localhost:8080/rest/factbook");  
 
        
 
        
 
     // Establish the connection to the URL.  
 
     // Establish the connection to the URL.  
Line 260: Line 312:
 
     String user = "bob";
 
     String user = "bob";
 
     String pw ="alice";
 
     String pw ="alice";
     // Encode user name and password pair with a base64 implementation.
+
     // Encode username and password pair with a base64 implementation.
 
     String encoded = Base64.encode(user + ":" + pw);
 
     String encoded = Base64.encode(user + ":" + pw);
 
     // Basic access authentication header to connection request.
 
     // Basic access authentication header to connection request.
Line 272: Line 324:
 
   }
 
   }
 
}
 
}
</pre>
+
</syntaxhighlight>
  
 
===Content-Types===
 
===Content-Types===
Line 279: Line 331:
 
the connection (in this example we explicitly store the input file as raw):
 
the connection (in this example we explicitly store the input file as raw):
  
<pre class="brush:java">
+
<syntaxhighlight lang="java">
 
// store input as raw
 
// store input as raw
 
conn.setRequestProperty("Content-Type", "application/octet-stream");
 
conn.setRequestProperty("Content-Type", "application/octet-stream");
</pre>
+
</syntaxhighlight>
  
 
See the [[REST#PUT Requests|PUT Requests]] section for a description of the possible content-types.
 
See the [[REST#PUT Requests|PUT Requests]] section for a description of the possible content-types.
Line 291: Line 343:
 
==Command Line==  
 
==Command Line==  
  
Tools such as the Linux commands [http://www.gnu.org/s/wget/ Wget] or [http://curl.haxx.se/ cURL] exist to
+
Tools such as the Linux commands [https://www.gnu.org/s/wget/ Wget] or [http://curl.haxx.se/ cURL] exist to
 
perform HTTP requests (try copy &amp; paste):
 
perform HTTP requests (try copy &amp; paste):
  
 
;GET  
 
;GET  
* <code><nowiki>curl -i "http://localhost:8984/rest/factbook?query=//city/name"</nowiki></code>
+
* <code><nowiki>curl -i "http://localhost:8080/rest/factbook?query=//city/name"</nowiki></code>
 
;POST
 
;POST
* <code><nowiki>curl -i -X POST -H "Content-Type: application/xml" -d "&lt;query xmlns='http://basex.org/rest'&gt;&lt;text&gt;//city/name&lt;/text&gt;&lt;/query&gt;" "http://localhost:8984/rest/factbook"</nowiki></code>
+
* <code><nowiki>curl -i -X POST -H "Content-Type: application/xml" -d "&lt;query xmlns='http://basex.org/rest'&gt;&lt;text&gt;//city/name&lt;/text&gt;&lt;/query&gt;" "http://localhost:8080/rest/factbook"</nowiki></code>
* <code><nowiki>curl -i -X POST -H "Content-Type: application/xml" -T query.xml "http://localhost:8984/rest/factbook"</nowiki></code>  
+
* <code><nowiki>curl -i -X POST -H "Content-Type: application/xml" -T query.xml "http://localhost:8080/rest/factbook"</nowiki></code>  
 
;PUT
 
;PUT
* <code><nowiki>curl -i -X PUT -T "etc/xml/factbook.xml" "http://localhost:8984/rest/factbook"</nowiki></code>
+
* <code><nowiki>curl -i -X PUT -T "etc/xml/factbook.xml" "http://localhost:8080/rest/factbook"</nowiki></code>
* <code><nowiki>curl -i -X PUT -H "Content-Type: application/json" -T "plain.json" "http://localhost:8984/rest/plain"</nowiki></code>
+
* <code><nowiki>curl -i -X PUT -H "Content-Type: application/json" -T "plain.json" "http://localhost:8080/rest/plain"</nowiki></code>
 
;DELETE
 
;DELETE
* <code><nowiki>curl -i -X DELETE "http://admin:admin@localhost:8984/rest/factbook"</nowiki></code>
+
* <code><nowiki>curl -i -X DELETE "http://admin:admin@localhost:8080/rest/factbook"</nowiki></code>
  
 
=Changelog=
 
=Changelog=
 +
 +
;Version 10.0
 +
* Updated: Results in the {{Code|rest}} namespace will be returned unprefixed.
 +
* Updated: {{Code|dir}} elements are returned when listing the contents of a database.
 +
 +
;Version 9.0
 +
* Added: Support for command scripts in the [[#POST Method|POST Method]].
 +
* Updated: The REST namespace in the [[#POST Method|POST Method]] has become optional.
  
 
;Version 8.1
 
;Version 8.1
* Added: support for input-specific content-type parameters
+
* Added: Support for input-specific content-type parameters
* Updated: the [[#GET Method|run operation]] now resolves file paths against the [[Options#RESTPATH|RESTPATH]] option.
+
* Updated: The [[#GET Method|run operation]] now resolves file paths against the {{Option|RESTPATH}} option.
  
 
;Version 8.0
 
;Version 8.0
Line 318: Line 378:
  
 
;Version 7.2
 
;Version 7.2
* Removed: direct evaluation of adresses resources with <code>application/xquery</code> as content type
+
* Removed: Direct evaluation of adresses resources with <code>application/xquery</code> as content type
  
 
;Version 7.1.1
 
;Version 7.1.1

Revision as of 09:29, 3 August 2022

This page presents one of the Web Application services. It describes how to use the REST API of BaseX.

BaseX offers a RESTful API for accessing database resources via URLs. REST (REpresentational State Transfer) facilitates a simple and fast access to databases through HTTP. The HTTP methods GET, PUT, DELETE, and POST can be used to interact with the database.

Usage

By default, REST services are available at http://localhost:8080/rest/. If no default credentials are specified in the URL or when starting the web application, they will be requested by the client (see further).

A web browser can be used to perform simple GET-based REST requests and display the response. Some alternatives for using REST are listed in the Usage Examples.

With BaseX 10, results in the rest namespace will be returned unprefixed:

<syntaxhighlight lang="xml"> <rest:databases xmlns:rest="http://basex.org/rest"/>

<databases xmlns="http://basex.org/rest"/> </syntaxhighlight>

URL Architecture

A request to the root URL returns all available databases:

http://localhost:8080/rest

<syntaxhighlight lang="xml"> <databases xmlns="http://basex.org/rest">

 <database resources="25742" size="43813599">articles</database>
 ...

</databases> </syntaxhighlight>

The resources of a database (directories, resource metadata) are listed if a database and an optional directory path is specified:

http://localhost:8080/rest/articles

<syntaxhighlight lang="xml"> <database name="articles" xmlns="http://basex.org/rest">

 <dir>binaries</dir>
 <resource type="xml" content-type="application/xml" size="77192">1973-02-08-xltp325.xml</resource>
 ...

</database> </syntaxhighlight>

The dir elements were introduced with Version 10. Before, information on all resources was listed that were located in the specified path or any of its subdirectories.

If the path to a single resource is specified, the resource itself will be returned:

http://localhost:8080/rest/articles/1973-02-08-xltp325.xml

Parameters

The following parameters can be applied to the operations:

  • Variables:
    External variables can be bound before a query is evaluated (see below for more).
  • Context:
    The context parameter may be used to provide an initial XML context node.
  • Options:
    Specified Options are applied before the actual operation will be performed.
  • Serialization:
    All Serialization parameters known to BaseX can be specified as query parameters. Parameters that are specified within a query will be interpreted by the REST server before the output is generated.

While Options can be specified for all operations, the remaining parameters will only make sense for Query and Run.

Request

GET Method

If the GET method is used, all query parameters are directly specified within the URL. Additionally, the following operations can be specified:

  • query: Evaluate an XQuery expression. If a database or database path is specified in the URL, it is set as query context.
  • command: Execute a single database command.
  • run: Evaluate an XQuery file or command script located on the server. The file path is resolved against the directory specified by RESTPATH (before, it was resolved against WEBPATH). Similar to query, a database or database path is set as context.
Examples

POST Method

The body of a POST request is interpreted as XML fragment, which specifies the operation to perform. The name of the root element determines how the body will be evaluated:

  • commands: Run Command Script
  • query: Execute XQuery expression
  • run: Run server-side file (query or command script)
  • command: Execute single command

The root element may be bound to the optional REST namespace. Existing command scripts can be sent to the server without any modifications:

  • Create an empty database and return database information:

<syntaxhighlight lang="xml"> <commands>

 <create-db name='db'/>
 <info-db/>

</commands> </syntaxhighlight>

For the other commands, the following child elements are supported:

Name Description
text Required; contains the query string, command string, or file to be run
parameter Serialization parameter (with @name and @value attributes)
option Database option (with @name and @value attributes)
variable Variable bindings
context Initial context item
Examples
  • Return the first five city names of the factbook database:

<syntaxhighlight lang="xml"> <rest xmlns="http://basex.org/rest">

 <rest><![CDATA[ (//city/name)[position() <= 5] ]]></text>

</rest> </syntaxhighlight>

  • Return string lengths of all text nodes that are found in the node that has been specified as initial context node:

<syntaxhighlight lang="xml"> <query>

 <text>for $i in .//text() return string-length($i)</text>
 <context>
   <xml>
     <text>Hello</text>
     <text>World</text>
   </xml>
 </context>

</query> </syntaxhighlight>

  • Return the registered database users encoded in ISO-8859-1:

<syntaxhighlight lang="xml"> <command>

 <text>show users</text>
 <parameter name='encoding' value='ISO-8859-1'/>

</command> </syntaxhighlight>

  • Create a new database from the specified input and preserve all whitespaces:

<syntaxhighlight lang="xml"> <command>

 <text>create db test http://files.basex.org/xml/xmark.xml</text>
 <option name='chop' value='false'/>

</command> </syntaxhighlight>

  • Bind value to the $person variable and run query find-person.xq, which must be located in the directory specified by WEBPATH:

<syntaxhighlight lang="xml"> <run>

 <variable name='person' value='Johannes Müller'/>
 <text>find-person.xq</text>

</run> </syntaxhighlight>

PUT Method

The PUT method is used to create new databases, or to add or update existing database resources:

  • Create Database:
    A new database is created if the URL only specifies the name of a database. If the request body contains XML, a single document is created, adopting the name of the database.
  • Store Resource:
    A resource is added to the database if the URL contains a database path. If the addressed resource already exists, it is replaced by the new input.

There are two ways to store non-XML data in BaseX:

  • Store as Raw Data:
    If application/octet-stream is chosen as content-type, the input is added as Binary Data.
  • Convert to XML:
    Incoming data is converted to XML if a parser is available for the specified content-type. The following content types are supported:
    • application/json: Stores JSON as XML.
    • text/plain: Stores plain text input as XML.
    • text/comma-separated-values: Stores CSV text input as XML.
    • text/html: Stores HTML input as XML.

Conversion can be influenced by specifying additional content-type parameters (see RESTXQ for more information).

If raw data is added and if no content type, or a wrong content, is specified, a 400 (BAD REQUEST) error will be raised.

Examples
  • A new database with the name XMark is created. If XML input is sent in the HTTP body, the resulting database resource will be called XMark.xml:
    http://localhost:8080/rest/XMark
  • A new database is created, and no whitespaces will be removed from the passed on XML input:
    http://localhost:8080/rest/XMark?chop=false
  • The contents of the HTTP body will be taken as input for the document one.xml, which will be stored in the XMark database:
    http://localhost:8080/rest/XMark/one.xml

An HTTP response with status code 201 (CREATED) is sent back if the operation was successful. Otherwise, the server will reply with 404 (if a specified database was not found) or 400 (if the operation could not be completed).

Have a look at the usage examples for more detailed examples using Java and shell tools like cURL.

DELETE Method

The DELETE method is used to delete databases or resources within a database.

Example
  • The factbook database is deleted:
    http://localhost:8080/rest/factbook
  • All resources of the XMark database are deleted that reside in the tmp path:
    http://localhost:8080/rest/XMark/tmp/

The HTTP status code 404 is returned if no database is specified. 200 (OK) will be sent in all other cases.

Assigning Variables

GET Method

All query parameters that have not been processed before will be treated as variable assignments:

Example

<syntaxhighlight lang="xquery"> (: XQuery file: mult.xq :) declare variable $a as xs:integer external; declare variable $b as xs:integer external; <mult>{ $a * $b }</mult> </syntaxhighlight>

The dollar sign can be omitted as long as the variable name does not equal a parameter keyword (e.g.: method).

POST Method

If query or run is used as operation, external variables can be specified via the <variable/> element:

<syntaxhighlight lang="xml"> <query xmlns="http://basex.org/rest">

 <text><![CDATA[
   declare variable $a as xs:integer external;
   declare variable $b as xs:integer external;
   <mult>{ $a * $b }</mult>
 ]]></text>
 <variable name="a" value="21"/>
 <variable name="b" value="2"/>

</query> </syntaxhighlight>

Response

Content Type

As the content type of a REST response cannot necessarily be dynamically determined, it can be enforced by the user. The final content type of a REST response is chosen as follows:

  1. If the serialization parameter media-type is supplied, it will be adopted as content-type.
  2. Otherwise, if the serialization parameter method is supplied, the content-type will be chosen according to the following mapping:
    • xml, adaptive, basexapplication/xml
    • xhtmltext/html
    • htmltext/html
    • texttext/plain
    • jsonapplication/json
  3. If no media-type or serialization method is supplied, the content type of a response depends on the chosen REST operation:
    • Query/Runapplication/xml
    • Commandtext/plain
    • Getapplication/xml, or content type of the addressed resource

Serialization parameters can either be supplied as query parameters or within the query.

The following three example requests all return <a/> with application/xml as content-type:

http://localhost:8080/rest?query=%3Ca/%3E
http://localhost:8080/rest?query=%3Ca/%3E&method=xml
http://localhost:8080/rest?query=%3Ca/%3E&media-type=application/xml

Usage Examples

Java

Authentication

Most programming languages offer libraries to communicate with HTTP servers. The following example demonstrates how easy it is to perform a DELETE request with Java.

Basic access authentication can be activated in Java by adding an authorization header to the HttpURLConnection instance. The header contains the word Basic, which specifies the authentication method, followed by the Base64-encoded USER:PASSWORD pair. As Java does not include a default conversion library for Base64 data, the internal BaseX class org.basex.util.Base64 can be used for that purpose:

<syntaxhighlight lang="java"> import java.net.*; import org.basex.util.*;

public final class RESTExample {

 public static void main(String[] args) throws Exception {
   // The java URL connection to the resource. 
   URL url = new URL("http://localhost:8080/rest/factbook"); 
     
   // Establish the connection to the URL. 
   HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 
   // Set as DELETE request. 
   conn.setRequestMethod("DELETE"); 
    
   // User and password.
   String user = "bob";
   String pw ="alice";
   // Encode username and password pair with a base64 implementation.
   String encoded = Base64.encode(user + ":" + pw);
   // Basic access authentication header to connection request.
   conn.setRequestProperty("Authorization", "Basic " + encoded);
     
   // Print the HTTP response code. 
   System.out.println("HTTP response: " + conn.getResponseCode()); 
     
   // Close connection. 
   conn.disconnect(); 
 }

} </syntaxhighlight>

Content-Types

The content-type of the input can easily be included, just add the following property to the connection (in this example we explicitly store the input file as raw):

<syntaxhighlight lang="java"> // store input as raw conn.setRequestProperty("Content-Type", "application/octet-stream"); </syntaxhighlight>

See the PUT Requests section for a description of the possible content-types.

Find Java examples for all methods here: GET, POST, PUT, DELETE.

Command Line

Tools such as the Linux commands Wget or cURL exist to perform HTTP requests (try copy & paste):

GET
  • curl -i "http://localhost:8080/rest/factbook?query=//city/name"
POST
  • curl -i -X POST -H "Content-Type: application/xml" -d "<query xmlns='http://basex.org/rest'><text>//city/name</text></query>" "http://localhost:8080/rest/factbook"
  • curl -i -X POST -H "Content-Type: application/xml" -T query.xml "http://localhost:8080/rest/factbook"
PUT
  • curl -i -X PUT -T "etc/xml/factbook.xml" "http://localhost:8080/rest/factbook"
  • curl -i -X PUT -H "Content-Type: application/json" -T "plain.json" "http://localhost:8080/rest/plain"
DELETE
  • curl -i -X DELETE "http://admin:admin@localhost:8080/rest/factbook"

Changelog

Version 10.0
  • Updated: Results in the rest namespace will be returned unprefixed.
  • Updated: dir elements are returned when listing the contents of a database.
Version 9.0
  • Added: Support for command scripts in the POST Method.
  • Updated: The REST namespace in the POST Method has become optional.
Version 8.1
  • Added: Support for input-specific content-type parameters
  • Updated: The run operation now resolves file paths against the RESTPATH option.
Version 8.0
  • Removed: wrap parameter
Version 7.9
  • Updated: Also evaluate command scripts via the run operation.
Version 7.2
  • Removed: Direct evaluation of adresses resources with application/xquery as content type
Version 7.1.1
  • Added: options parameter for specifying database options
Version 7.1
  • Added: PUT request: automatic conversion to XML if known content type is specified
Version 7.0
  • REST API introduced, replacing the old JAX-RX API