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Symbian OS Library

SYMBIAN OS V9.3

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How to create a URI

You can create a URI by one of the following 4 methods using CUri8 and UriUtils classes:

  1. Create from parts (components)

  2. Create from the filename

  3. Create from relative URIs

  4. Create from a unicode descriptor


Creating a URI from parts

You can create a URI by adding each component. This is done by calling CUri8::SetComponentL() repeatedly for each component. CUri8 supports modification of URI components. It also provides reference to a TUriC8 object to use the non-modifying functionality that is provided by TUriC8.

The code below constructs a CUri object from parts such as scheme, host and user info components.

TUriC8 pUri;
CUri8* uri = CUri8::NewL(pUri); //create a pointer to CUri8 object, pass a reference to a parsed TUriC8 object 

NewL() and NewLC() methods have overloads that construct an empty URI object.

// Add components to build a URI
_LIT8(KScheme0,     "http");
    _LIT8(KHost0,       "www.mypage.com");
    _LIT8(KUserInfo0,   "user:pass");

    CUri8* uri = CUri8::NewLC();
    uri->SetComponentL(KScheme0, EUriScheme); //set the scheme component
    uri->SetComponentL(KHost0, EUriHost); //set the host component
    uri->SetComponentL(KUserInfo0, EUriUserinfo); //set the user info component
    const TDesC8& des = uri->Uri().UriDes();/ / retrieve the created URI

The descriptor des contains the URI "http://user:[email protected]".

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Removing a component

You can remove a specific component from a URI using CUri8::RemoveComponentL(). The code below removes the scheme component of the URI. If the component does not exist, this function does nothing.

uri8->RemoveComponentL(EUriScheme);  //remove the scheme component
    const TDesC8& des8 = uri8->Uri().UriDes();  //retrieve the URI

des contains the remaining part of URI that is "user:[email protected]", after removing "http", the scheme component.

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Creating authority components

Similar to a URI, authority components can be created from its components. This is done by adding the user info, host and port by calling CAuthority8::SetComponentL() repeatedly.

Parse the component that needs to be added calling TAuthorityParser8::Parse() and create an object using CAuthority8::NewL().

TAuthorityParser8 authorityParser;
    _LIT8(KAuthority,"www.symbian.com");
    authorityParser.Parse(KAuthority);//parse the authority component
    
    CAuthority8* authority = CAuthority8::NewL(authorityParser);// create an authority object
    // Add components to the Authority 
    _LIT8(KUserinfo,"user:info");
    authority->SetComponentL(KUserinfo,EAuthorityUserinfo);//set the userinfo 
    _LIT8(KHost, "www.symbian.com");
    authority->SetComponentL(KHost,EAuthorityHost);//set the host 
    _LIT8(KPort,"80");
    authority->SetComponentL(KPort,EAuthorityPort); //set the port 
    
    const TDesC8& authorityDes = authority->Authority().AuthorityDes(); // get the authority component

authorityDes descriptor contains the complete authority component "user:[email protected]:80".

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Setting and escaping authority component

CAuthority8::SetAndEscapeComponentL() allows you to escape encode and set the authority component in a URI. This escapes any unsafe data before setting the component.

CAuthority8* authority = CAuthority8::NewL(authorityParser);
authority->SetAndEscapeComponentL(KUserinfo,EAuthorityUserinfo); //escape encode and set user info component  

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Removing authority component

CAuthority8::RemoveComponentL() removes a component, specified with a TAuthorityComponent component, from the authority data.

//Remove the user info component from the URI
authority->RemoveComponentL(EAuthorityUserinfo);

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Creating a URI from the filename

To create a file URI object, call CUri8::CreateFileUriL().

The code fragment below creates the file URI object.

//Set the physical path of the file
LIT(KFullUriName, "D:\\MyFolder\\MyDoc.doc");
//create the Uri for the path component 
CUri8* pathUri8 = CUri8::CreateFileUriL(KFullUriName,0);

The code returns the URI for the specified file path. Provide the full file name descriptor. For example, D:\\MyFolder\\MyDoc.doc and specify whether the drive on which the file exists is fixed or external. 0 indicates a fixed drive, otherwise specify EExtMedia.

If the file exists on:

  1. a fixed drive, then the URI takes the form file:///private/<drive-letter>/<filepath>

  2. a removable drive, then the URI takes the form file:///ext-media/<filepath> or file:///private/ext-media/<filepath> .

If the file is private to the application, then use CUri8::CreatePrivateFileUriL() instead of CUri8::CreateFileUriL().

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Creating a URI from relative URIs

This section explains how to create URIs from base and reference URIs.

Resolving

Resolving is the process of interpreting what the string means, stripping it into some component parts and then using those to decide on the following:

  1. How to look something up interpreting the raw content that was sent back to us.

  2. What we want to look up for that identifier.

  3. Once we have looked it up, what protocol is needed to acquire it.

  4. Interpreting the raw content that was sent back to us.

The first one is called resolving. In this context, resolving is the process of converting a relative URI reference (for example, ../../../resource.txt) to its absolute form, for example, http://somehost/resource.txt.

You need to resolve the URI to know what the identifier actually points to.

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Creating a URI by resolving

The code below resolves the reference URI against the base URI and returns an absolute URI.

Create the base and reference URIs from its components using SetComponentL(). Refer to Creating a URI from parts.

_LIT8(KBase,"http://www.mypage.com/folder1/folder2/index.html");
    _LIT8(KReference,       "../../empdetail.html");
    
    TUriParser8 baseUri;//base URI object
    TInt error = baseUri.Parse(KBase);//parse the base URI
            
    TUriParser8 refUri;//reference URI object
    error = refUri.Parse(KReference);/parse the reference URI
            
        
    CUri8* resolvedUri = NULL;
    resolvedUri = CUri8::ResolveL(baseUri, refUri); //resolve the reference URI against base URI
    const TDesC8& des1 = resolvedUri->Uri().UriDes(); //retrieve the resolved URI

The code above resolves the reference URI against the base URI and returns an absolute URI, "http://www.mypage.com/empdetail.html" in this case.

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Creating a URI from a descriptor

UriUtils::CreateUriL() creates a CUri8 object from a Unicode descriptor.

_LIT8(KUri,"http://web.intra/Dev/Sysdoc/devlib.htm");
CUri8* uri8= UriUtils::CreateUriL(KUri);

This returns a new CUri8 object. It returns EUriUtilsParserErrInvalidUri if the descriptor is an invalid URI.

You can create an authority component of URI from a descriptor calling UriUtils::CreateAuthorityL().

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See also

For related information, see:

InetProtUtils Overview

Using URI utilities