io.netty.handler.codec.http

Class QueryStringDecoder

java.lang.Object

io.netty.handler.codec.http.QueryStringDecoder

public class QueryStringDecoder
extends Object

Splits an HTTP query string into a path string and key-value parameter pairs. This decoder is for one time use only. Create a new instance for each URI:

 QueryStringDecoder decoder = new QueryStringDecoder("/hello?recipient=world&x=1;y=2");
 assert decoder.path().equals("/hello");
 assert decoder.parameters().get("recipient").get(0).equals("world");
 assert decoder.parameters().get("x").get(0).equals("1");
 assert decoder.parameters().get("y").get(0).equals("2");
 

This decoder can also decode the content of an HTTP POST request whose content type is application/x-www-form-urlencoded:

 QueryStringDecoder decoder = new QueryStringDecoder("recipient=world&x=1;y=2", false);
 ...
 

HashDOS vulnerability fix

As a workaround to the HashDOS vulnerability, the decoder limits the maximum number of decoded key-value parameter pairs, up to 1024 by default, and you can configure it when you construct the decoder by passing an additional integer parameter.

See Also:

QueryStringEncoder

Constructor Summary

Constructors

Constructor and Description
QueryStringDecoder(String uri) Creates a new decoder that decodes the specified URI.
QueryStringDecoder(String uri, boolean hasPath) Creates a new decoder that decodes the specified URI encoded in the specified charset.
QueryStringDecoder(String uri, Charset charset) Creates a new decoder that decodes the specified URI encoded in the specified charset.
QueryStringDecoder(String uri, Charset charset, boolean hasPath) Creates a new decoder that decodes the specified URI encoded in the specified charset.
QueryStringDecoder(String uri, Charset charset, boolean hasPath, int maxParams) Creates a new decoder that decodes the specified URI encoded in the specified charset.
QueryStringDecoder(URI uri) Creates a new decoder that decodes the specified URI.
QueryStringDecoder(URI uri, Charset charset) Creates a new decoder that decodes the specified URI encoded in the specified charset.
QueryStringDecoder(URI uri, Charset charset, int maxParams) Creates a new decoder that decodes the specified URI encoded in the specified charset.

Method Summary

Modifier and Type	Method and Description
static String	decodeComponent(String s) Decodes a bit of an URL encoded by a browser.
static String	decodeComponent(String s, Charset charset) Decodes a bit of an URL encoded by a browser.
Map<String,List<String>>	parameters() Returns the decoded key-value parameter pairs of the URI.
String	path() Returns the decoded path string of the URI.
String	uri() Returns the uri used to initialize this QueryStringDecoder.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

QueryStringDecoder

public QueryStringDecoder(String uri)

Creates a new decoder that decodes the specified URI. The decoder will assume that the query string is encoded in UTF-8.

QueryStringDecoder

public QueryStringDecoder(String uri,
                          boolean hasPath)

Creates a new decoder that decodes the specified URI encoded in the specified charset.

QueryStringDecoder

public QueryStringDecoder(String uri,
                          Charset charset)

Creates a new decoder that decodes the specified URI encoded in the specified charset.

QueryStringDecoder

public QueryStringDecoder(String uri,
                          Charset charset,
                          boolean hasPath)

Creates a new decoder that decodes the specified URI encoded in the specified charset.

QueryStringDecoder

public QueryStringDecoder(String uri,
                          Charset charset,
                          boolean hasPath,
                          int maxParams)

Creates a new decoder that decodes the specified URI encoded in the specified charset.

QueryStringDecoder

public QueryStringDecoder(URI uri)

Creates a new decoder that decodes the specified URI. The decoder will assume that the query string is encoded in UTF-8.

QueryStringDecoder

public QueryStringDecoder(URI uri,
                          Charset charset)

Creates a new decoder that decodes the specified URI encoded in the specified charset.

QueryStringDecoder

public QueryStringDecoder(URI uri,
                          Charset charset,
                          int maxParams)

Creates a new decoder that decodes the specified URI encoded in the specified charset.

Method Detail

uri

public String uri()

Returns the uri used to initialize this QueryStringDecoder.

path

public String path()

Returns the decoded path string of the URI.

parameters

public Map<String,List<String>> parameters()

Returns the decoded key-value parameter pairs of the URI.

decodeComponent

public static String decodeComponent(String s)

Decodes a bit of an URL encoded by a browser.

This is equivalent to calling decodeComponent(String, Charset) with the UTF-8 charset (recommended to comply with RFC 3986, Section 2).

Parameters:

s - The string to decode (can be empty).

Returns:

The decoded string, or s if there's nothing to decode. If the string to decode is null, returns an empty string.

Throws:

IllegalArgumentException - if the string contains a malformed escape sequence.

decodeComponent

public static String decodeComponent(String s,
                                     Charset charset)

Decodes a bit of an URL encoded by a browser.

The string is expected to be encoded as per RFC 3986, Section 2. This is the encoding used by JavaScript functions encodeURI and encodeURIComponent, but not escape. For example in this encoding, é (in Unicode U+00E9 or in UTF-8 0xC3 0xA9) is encoded as %C3%A9 or %c3%a9.

This is essentially equivalent to calling URLDecoder.decode(s, charset.name()) except that it's over 2x faster and generates less garbage for the GC. Actually this function doesn't allocate any memory if there's nothing to decode, the argument itself is returned.

Parameters:

s - The string to decode (can be empty).

charset - The charset to use to decode the string (should really be CharsetUtil.UTF_8.

Returns:

The decoded string, or s if there's nothing to decode. If the string to decode is null, returns an empty string.

Throws:

IllegalArgumentException - if the string contains a malformed escape sequence.