Escape +Encoding and Decoding

This tutorial describes the steps to escape encoding and decoding.

Introduction

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.

Escape encoding

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"

EscapeUtils::EscapeEncodeL() escape +encodes the invalid and reserved characters in the data as escape triples. +The reserved characters and the set of excluded characters specified by RFC 2396 (refer +to the above table) form the entire set of excluded data.

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 TEscapeMode, refer to the +table in Reservered +characters section.

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); +

Escape encoding is ideal during creation of URI from the components.

Escape decoding

EscapeUtils::EscapeDecodeL() escape +decodes the data. This code escape decodes the data '%20%3C%3E%23%25%22%7B%7D%7C%5C%5E%60' +to '<>#%\"{}|\\^'.

_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); +

The URI must be split into its components before +the escaped characters within the components are safely decoded.