<?xml version="1.0" encoding="utf-8"?>

<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

<!-- This component and the accompanying materials are made available under the terms of the License 

"Eclipse Public License v1.0" which accompanies this distribution, 

and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->

<!-- Initial Contributors:

    Nokia Corporation - initial contribution.

Contributors: 

-->

<!DOCTYPE concept

  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

<concept id="GUID-0E8206E9-4F1D-5DF5-8A69-9B0831061CFF" xml:lang="en"><title>Escape

Encoding and Decoding</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>This tutorial describes the steps to escape encoding and decoding. </p>

<section><title>Introduction</title> <p>Reserved, unsafe and unreserved characters

present a possibility of being interpreted incorrectly when used in the URIs.

To avoid this, these characters must be escape encoded and decoded. </p> </section>

<section><title>Escape encoding </title><p>URI encoding of a character consists

of a "%" symbol, followed by two hexadecimal digits representing the octet

code. For example, Space = decimal code point 32 in the ISO-Latin set. 32

decimal = 20 in hexadecimal. The URI encoded representation will be "%20" </p> <p> <xref href="GUID-9CC256C4-D4A2-3534-9B3C-2FBF1AAE5F51.dita#GUID-9CC256C4-D4A2-3534-9B3C-2FBF1AAE5F51/GUID-26C9B121-B619-33EF-98A3-E65787C3A9BF"><apiname>EscapeUtils::EscapeEncodeL()</apiname></xref> escape

encodes the invalid and reserved characters in the data as escape triples.

The reserved characters and the set of excluded characters specified by <xref href="http://www.ietf.org/rfc/rfc2396.txt" scope="external">RFC 2396</xref> (refer

to the above table) form the entire set of excluded data. </p> <p>The following

code fragment checks for the invalid and reserved characters in the authority

component of an URI and returns the string with these characters escape encoded.

For other modes as defined in <xref href="GUID-0B61C1D3-7DAB-3149-932F-1F96A84EDF42.dita"><apiname>TEscapeMode</apiname></xref>, refer to the

table in <xref href="GUID-E0DC9706-AAC5-5950-86E8-D667A7AFCD49.dita#GUID-E0DC9706-AAC5-5950-86E8-D667A7AFCD49/GUID-B5EB7F55-60AF-5703-96F6-0C42A3D433EE">Reservered

characters</xref> section. </p> <codeblock id="GUID-D0CBCEA3-59F2-50E0-AC4D-473FC5DF24E9" xml:space="preserve">HBufC16* encode = EscapeUtils::EscapeEncodeL(*decode,  EscapeUtils::EEscapeAuth);

CleanupStack::PushL(encode);//encode contains %20%3C%3E%23%25%22%7B%7D%7C%5C%5E%60

......//use encode here

CleanupStack::PopAndDestroy(encode);

</codeblock> <p>Escape encoding is ideal during creation of URI from the components. </p> </section>

<section><title>Escape decoding </title><p> <xref href="GUID-9CC256C4-D4A2-3534-9B3C-2FBF1AAE5F51.dita#GUID-9CC256C4-D4A2-3534-9B3C-2FBF1AAE5F51/GUID-B4149EF0-0E1D-3F80-9974-165DF17105E9"><apiname>EscapeUtils::EscapeDecodeL()</apiname></xref> escape

decodes the data. This code escape decodes the data '<codeph>%20%3C%3E%23%25%22%7B%7D%7C%5C%5E%60</codeph>'

to '<codeph>&lt;&gt;#%\"{}|\\^</codeph>'. </p> <codeblock id="GUID-F0A7F46E-F5DF-52CE-8334-AD7789208F97" xml:space="preserve">_LIT(KEscapeEncoded, %20%3C%3E%23%25%22%7B%7D%7C%5C%5E%60);        //data to decode

HBufC16* decode = EscapeUtils::EscapeDecodeL(KEscapeEncoded); //contains <>#%\"{}|\\^`

CleanupStack::PushL(decode);

...........................

CleanupStack::PopAndDestroy(decode);

          </codeblock> <p>The URI must be split into its components before

the escaped characters within the components are safely decoded. </p></section>

</conbody><related-links>

<link href="GUID-795B41AF-FBEA-56CE-AE20-EF17BE754723.dita"><linktext>HTTP Utilities

Library Overview</linktext></link>

<link href="GUID-853BFDC0-1993-5EFC-AA68-C9EA496EEF3F.dita"><linktext>Converting

between Unicode and Utf8</linktext></link>

<link href="GUID-E0DC9706-AAC5-5950-86E8-D667A7AFCD49.dita"><linktext>Reserved

and unreserved characters</linktext></link>