QUrl Class Reference

 #include <QUrl>

Member Function Documentation

QUrl::QUrl ()

Constructs an empty QUrl object.

QUrl::QUrl ( const QString & url )

Constructs a URL by parsing url. url is assumed to be in human readable representation, with no percent encoding. QUrl will automatically percent encode all characters that are not allowed in a URL.

Example:

 QUrl url("http://www.example.com/List of holidays.xml");
 // url.toEncoded() == "http://www.example.com/List%20of%20holidays.xml"

To construct a URL from an encoded string, call fromEncoded():

 QUrl url = QUrl::fromEncoded("http://qt.nokia.com/List%20of%20holidays.xml");

See also setUrl(), setEncodedUrl(), fromEncoded(), and TolerantMode.

QUrl::QUrl ( const QUrl & other )

Constructs a copy of other.

QUrl::QUrl ( const QString & url, ParsingMode parsingMode )

This is an overloaded function.

Parses the url using the parser mode parsingMode.

See also setUrl().

QUrl::~QUrl ()

Destructor; called immediately before the object is deleted.

void QUrl::addEncodedQueryItem ( const QByteArray & key, const QByteArray & value )

Inserts the pair key = value into the query string of the URL.

Note: this function does not verify that either key or value are properly encoded. It is the caller's responsibility to ensure that the query delimiters are properly encoded, if any.

This function was introduced in Qt 4.4.

See also addQueryItem() and setQueryDelimiters().

void QUrl::addQueryItem ( const QString & key, const QString & value )

Inserts the pair key = value into the query string of the URL.

The key/value pair is encoded before it is added to the query. The pair is converted into separate strings internally. The key and value is first encoded into UTF-8 and then delimited by the character returned by valueDelimiter(). Each key/value pair is delimited by the character returned by pairDelimiter().

Note: This method does not encode spaces (ASCII 0x20) as plus (+) signs, like HTML forms do. If you need that kind of encoding, you must encode the value yourself and use QUrl::addEncodedQueryItem.

See also addEncodedQueryItem().

QList<QByteArray> QUrl::allEncodedQueryItemValues ( const QByteArray & key ) const

Returns the a list of query string values whose key is equal to key from the URL.

Note: if the encoded key does not match the encoded version of the query, this function will not work. That is, if the encoded query of this URL is "search=Qt%20Rules", calling this function with key = "%73earch" will return an empty list.

This function was introduced in Qt 4.4.

See also allQueryItemValues(), queryItemValue(), and encodedQueryItemValue().

QStringList QUrl::allQueryItemValues ( const QString & key ) const

Returns the a list of query string values whose key is equal to key from the URL.

Note: This method does not decode spaces plus (+) signs as spaces (ASCII 0x20), like HTML forms do. If you need that kind of decoding, you must use QUrl::allEncodedQueryItemValues and decode the data yourself.

See also queryItemValue().

QString QUrl::authority () const

Returns the authority of the URL if it is defined; otherwise an empty string is returned.

See also setAuthority().

void QUrl::clear ()

Resets the content of the QUrl. After calling this function, the QUrl is equal to one that has been constructed with the default empty constructor.

QByteArray QUrl::encodedFragment () const

Returns the fragment of the URL if it is defined; otherwise an empty string is returned. The returned value will have its non-ASCII and other control characters percent-encoded, as in toEncoded().

This function was introduced in Qt 4.4.

See also setEncodedFragment() and toEncoded().

QByteArray QUrl::encodedHost () const

Returns the host part of the URL if it is defined; otherwise an empty string is returned.

Note: encodedHost() does not return percent-encoded hostnames. Instead, the ACE-encoded (bare ASCII in Punycode encoding) form will be returned for any non-ASCII hostname.

This function is equivalent to calling QUrl::toAce() on the return value of host().

This function was introduced in Qt 4.4.

See also setEncodedHost().

QByteArray QUrl::encodedPassword () const

Returns the password of the URL if it is defined; otherwise an empty string is returned. The returned value will have its non-ASCII and other control characters percent-encoded, as in toEncoded().

This function was introduced in Qt 4.4.

See also setEncodedPassword() and toEncoded().

QByteArray QUrl::encodedPath () const

Returns the path of the URL if it is defined; otherwise an empty string is returned. The returned value will have its non-ASCII and other control characters percent-encoded, as in toEncoded().

This function was introduced in Qt 4.4.

See also setEncodedPath() and toEncoded().

QByteArray QUrl::encodedQuery () const

Returns the query string of the URL in percent encoded form.

See also setEncodedQuery().

QByteArray QUrl::encodedQueryItemValue ( const QByteArray & key ) const

Returns the first query string value whose key is equal to key from the URL.

Note: if the encoded key does not match the encoded version of the query, this function will not work. That is, if the encoded query of this URL is "search=Qt%20Rules", calling this function with key = "%73earch" will return an empty string.

This function was introduced in Qt 4.4.

See also queryItemValue() and allQueryItemValues().

QList<QPair<QByteArray, QByteArray> > QUrl::encodedQueryItems () const

Returns the query string of the URL, as a map of encoded keys and values.

This function was introduced in Qt 4.4.

See also setEncodedQueryItems(), setQueryItems(), and setEncodedQuery().

QByteArray QUrl::encodedUserName () const

Returns the user name of the URL if it is defined; otherwise an empty string is returned. The returned value will have its non-ASCII and other control characters percent-encoded, as in toEncoded().

This function was introduced in Qt 4.4.

See also setEncodedUserName().

QString QUrl::errorString () const

Returns a text string that explains why an URL is invalid in the case being; otherwise returns an empty string.

This function was introduced in Qt 4.2.

QString QUrl::fragment () const

Returns the fragment of the URL.

See also setFragment().

QString QUrl::fromAce ( const QByteArray & domain ) [static]

Returns the Unicode form of the given domain name domain, which is encoded in the ASCII Compatible Encoding (ACE). The result of this function is considered equivalent to domain.

If the value in domain cannot be encoded, it will be converted to QString and returned.

The ASCII Compatible Encoding (ACE) is defined by RFC 3490, RFC 3491 and RFC 3492. It is part of the Internationalizing Domain Names in Applications (IDNA) specification, which allows for domain names (like "example.com") to be written using international characters.

This function was introduced in Qt 4.2.

QUrl QUrl::fromEncoded ( const QByteArray & input ) [static]

Parses input and returns the corresponding QUrl. input is assumed to be in encoded form, containing only ASCII characters.

The URL is parsed using TolerantMode.

See also toEncoded() and setUrl().

QUrl QUrl::fromEncoded ( const QByteArray & input, ParsingMode parsingMode ) [static]

This is an overloaded function.

Parses the URL using parsingMode.

See also toEncoded() and setUrl().

QUrl QUrl::fromLocalFile ( const QString & localFile ) [static]

Returns a QUrl representation of localFile, interpreted as a local file.

See also toLocalFile().

QString QUrl::fromPercentEncoding ( const QByteArray & input ) [static]

Returns a decoded copy of input. input is first decoded from percent encoding, then converted from UTF-8 to unicode.

QUrl QUrl::fromUserInput ( const QString & userInput ) [static]

Returns a valid URL from a user supplied userInput string if one can be deducted. In the case that is not possible, an invalid QUrl() is returned.

Most applications that can browse the web, allow the user to input a URL in the form of a plain string. This string can be manually typed into a location bar, obtained from the clipboard, or passed in via command line arguments.

When the string is not already a valid URL, a best guess is performed, making various web related assumptions.

In the case the string corresponds to a valid file path on the system, a file:// URL is constructed, using QUrl::fromLocalFile().

If that is not the case, an attempt is made to turn the string into a http:// or ftp:// URL. The latter in the case the string starts with 'ftp'. The result is then passed through QUrl's tolerant parser, and in the case or success, a valid QUrl is returned, or else a QUrl().

Examples:

• qt.nokia.com becomes http://qt.nokia.com
• ftp.qt.nokia.com becomes ftp://ftp.qt.nokia.com
• hostname becomes http://hostname
• /home/user/test.html becomes file:///home/user/test.html

Tips to avoid erroneous character conversion when dealing with

URLs and strings:

• When creating an URL QString from a QByteArray or a char*, always use QString::fromUtf8().
• Favor the use of QUrl::fromEncoded() and QUrl::toEncoded() instead of QUrl(string) and QUrl::toString() when converting QUrl to/from string.

This function was introduced in Qt 4.6.

bool QUrl::hasEncodedQueryItem ( const QByteArray & key ) const

Returns true if there is a query string pair whose key is equal to key from the URL.

Note: if the encoded key does not match the encoded version of the query, this function will return false. That is, if the encoded query of this URL is "search=Qt%20Rules", calling this function with key = "%73earch" will return false.

This function was introduced in Qt 4.4.

See also hasQueryItem().

bool QUrl::hasFragment () const

Returns true if this URL contains a fragment (i.e., if # was seen on it).

This function was introduced in Qt 4.2.

See also fragment() and setFragment().

bool QUrl::hasQuery () const

Returns true if this URL contains a Query (i.e., if ? was seen on it).

This function was introduced in Qt 4.2.

See also hasQueryItem() and encodedQuery().

bool QUrl::hasQueryItem ( const QString & key ) const

Returns true if there is a query string pair whose key is equal to key from the URL.

See also hasEncodedQueryItem().

QString QUrl::host () const

Returns the host of the URL if it is defined; otherwise an empty string is returned.

See also setHost().

QStringList QUrl::idnWhitelist () [static]

Returns the current whitelist of top-level domains that are allowed to have non-ASCII characters in their compositions.

See setIdnWhitelist() for the rationale of this list.

This function was introduced in Qt 4.2.

See also setIdnWhitelist().

bool QUrl::isEmpty () const

Returns true if the URL has no data; otherwise returns false.

bool QUrl::isParentOf ( const QUrl & childUrl ) const

Returns true if this URL is a parent of childUrl. childUrl is a child of this URL if the two URLs share the same scheme and authority, and this URL's path is a parent of the path of childUrl.

bool QUrl::isRelative () const

Returns true if the URL is relative; otherwise returns false. A URL is relative if its scheme is undefined; this function is therefore equivalent to calling scheme().isEmpty().

bool QUrl::isValid () const

Returns true if the URL is valid; otherwise returns false.

The URL is run through a conformance test. Every part of the URL must conform to the standard encoding rules of the URI standard for the URL to be reported as valid.

 bool checkUrl(const QUrl &url) {
     if (!url.isValid()) {
         qDebug(QString("Invalid URL: %1").arg(url.toString()));
         return false;
     }

     return true;
 }

QString QUrl::password () const

Returns the password of the URL if it is defined; otherwise an empty string is returned.

See also setPassword().

QString QUrl::path () const

Returns the path of the URL.

See also setPath().

int QUrl::port () const

Returns the port of the URL, or -1 if the port is unspecified.

See also setPort().

int QUrl::port ( int defaultPort ) const

This is an overloaded function.

Returns the port of the URL, or defaultPort if the port is unspecified.

Example:

 QFtp ftp;
 ftp.connectToHost(url.host(), url.port(21));

This function was introduced in Qt 4.1.

QString QUrl::queryItemValue ( const QString & key ) const

Returns the first query string value whose key is equal to key from the URL.

Note: This method does not decode spaces plus (+) signs as spaces (ASCII 0x20), like HTML forms do. If you need that kind of decoding, you must use QUrl::encodedQueryItemValue and decode the data yourself.

See also allQueryItemValues().

QList<QPair<QString, QString> > QUrl::queryItems () const

Returns the query string of the URL, as a map of keys and values.

Note: This method does not decode spaces plus (+) signs as spaces (ASCII 0x20), like HTML forms do. If you need that kind of decoding, you must use QUrl::encodedQueryItems and decode the data yourself.

See also setQueryItems() and setEncodedQuery().

char QUrl::queryPairDelimiter () const

Returns the character used to delimit between key-value pairs in the query string of the URL.

char QUrl::queryValueDelimiter () const

Returns the character used to delimit between keys and values in the query string of the URL.

void QUrl::removeAllEncodedQueryItems ( const QByteArray & key )

Removes all the query string pairs whose key is equal to key from the URL.

Note: if the encoded key does not match the encoded version of the query, this function will not work. That is, if the encoded query of this URL is "search=Qt%20Rules", calling this function with key = "%73earch" will do nothing.

This function was introduced in Qt 4.4.

See also removeQueryItem().

void QUrl::removeAllQueryItems ( const QString & key )

Removes all the query string pairs whose key is equal to key from the URL.

See also removeQueryItem().

void QUrl::removeEncodedQueryItem ( const QByteArray & key )

Removes the first query string pair whose key is equal to key from the URL.

Note: if the encoded key does not match the encoded version of the query, this function will not work. That is, if the encoded query of this URL is "search=Qt%20Rules", calling this function with key = "%73earch" will do nothing.

This function was introduced in Qt 4.4.

See also removeQueryItem() and removeAllQueryItems().

void QUrl::removeQueryItem ( const QString & key )

Removes the first query string pair whose key is equal to key from the URL.

See also removeAllQueryItems().

QUrl QUrl::resolved ( const QUrl & relative ) const

Returns the result of the merge of this URL with relative. This URL is used as a base to convert relative to an absolute URL.

If relative is not a relative URL, this function will return relative directly. Otherwise, the paths of the two URLs are merged, and the new URL returned has the scheme and authority of the base URL, but with the merged path, as in the following example:

 QUrl baseUrl("http://qt.nokia.com/support");
 QUrl relativeUrl("../products/solutions");
 qDebug(baseUrl.resolved(relativeUrl).toString());
 // prints "http://qt.nokia.com/products/solutions"

Calling resolved() with ".." returns a QUrl whose directory is one level higher than the original. Similarly, calling resolved() with "../.." removes two levels from the path. If relative is "/", the path becomes "/".

See also isRelative().

QString QUrl::scheme () const

Returns the scheme of the URL. If an empty string is returned, this means the scheme is undefined and the URL is then relative.

See also setScheme() and isRelative().

void QUrl::setAuthority ( const QString & authority )

Sets the authority of the URL to authority.

The authority of a URL is the combination of user info, a host name and a port. All of these elements are optional; an empty authority is therefore valid.

The user info and host are separated by a '@', and the host and port are separated by a ':'. If the user info is empty, the '@' must be omitted; although a stray ':' is permitted if the port is empty.

The following example shows a valid authority string:

See also authority().

void QUrl::setEncodedFragment ( const QByteArray & fragment )

Sets the URL's fragment to the percent-encoded fragment. The fragment is the last part of the URL, represented by a '#' followed by a string of characters. It is typically used in HTTP for referring to a certain link or point on a page:

The fragment is sometimes also referred to as the URL "reference".

Passing an argument of QByteArray() (a null QByteArray) will unset the fragment. Passing an argument of QByteArray("") (an empty but not null QByteArray) will set the fragment to an empty string (as if the original URL had a lone "#").

This function was introduced in Qt 4.4.

See also setFragment() and encodedFragment().

void QUrl::setEncodedHost ( const QByteArray & host )

Sets the URL's host to the ACE- or percent-encoded host. The host is part of the user info element in the authority of the URL, as described in setAuthority().

This function was introduced in Qt 4.4.

See also setHost(), encodedHost(), setAuthority(), and fromAce().

void QUrl::setEncodedPassword ( const QByteArray & password )

Sets the URL's password to the percent-encoded password. The password is part of the user info element in the authority of the URL, as described in setUserInfo().

Note: this function does not verify that password is properly encoded. It is the caller's responsibility to ensure that the any delimiters (such as colons or slashes) are properly encoded.

This function was introduced in Qt 4.4.

See also setPassword(), encodedPassword(), and setUserInfo().

void QUrl::setEncodedPath ( const QByteArray & path )

Sets the URL's path to the percent-encoded path. The path is the part of the URL that comes after the authority but before the query string.

For non-hierarchical schemes, the path will be everything following the scheme declaration, as in the following example:

Note: this function does not verify that path is properly encoded. It is the caller's responsibility to ensure that the any delimiters (such as '?' and '#') are properly encoded.

This function was introduced in Qt 4.4.

See also setPath(), encodedPath(), and setUserInfo().

void QUrl::setEncodedQuery ( const QByteArray & query )

Sets the query string of the URL to query. The string is inserted as-is, and no further encoding is performed when calling toEncoded().

This function is useful if you need to pass a query string that does not fit into the key-value pattern, or that uses a different scheme for encoding special characters than what is suggested by QUrl.

Passing a value of QByteArray() to query (a null QByteArray) unsets the query completely. However, passing a value of QByteArray("") will set the query to an empty value, as if the original URL had a lone "?".

See also encodedQuery() and hasQuery().

void QUrl::setEncodedQueryItems ( const QList<QPair<QByteArray, QByteArray> > & query )

Sets the query string of the URL to the encoded version of query. The contents of query are converted to a string internally, each pair delimited by the character returned by pairDelimiter(), and the key and value are delimited by valueDelimiter().

Note: this function does not verify that the key-value pairs are properly encoded. It is the caller's responsibility to ensure that the query delimiters are properly encoded, if any.

This function was introduced in Qt 4.4.

See also setQueryDelimiters(), encodedQueryItems(), and setQueryItems().

void QUrl::setEncodedUrl ( const QByteArray & encodedUrl )

Constructs a URL by parsing the contents of encodedUrl.

encodedUrl is assumed to be a URL string in percent encoded form, containing only ASCII characters.

Use isValid() to determine if a valid URL was constructed.

See also setUrl().

void QUrl::setEncodedUrl ( const QByteArray & encodedUrl, ParsingMode parsingMode )

Constructs a URL by parsing the contents of encodedUrl using the given parsingMode.

void QUrl::setEncodedUserName ( const QByteArray & userName )

Sets the URL's user name to the percent-encoded userName. The userName is part of the user info element in the authority of the URL, as described in setUserInfo().

Note: this function does not verify that userName is properly encoded. It is the caller's responsibility to ensure that the any delimiters (such as colons or slashes) are properly encoded.

This function was introduced in Qt 4.4.

See also setUserName(), encodedUserName(), and setUserInfo().

void QUrl::setFragment ( const QString & fragment )

Sets the fragment of the URL to fragment. The fragment is the last part of the URL, represented by a '#' followed by a string of characters. It is typically used in HTTP for referring to a certain link or point on a page:

The fragment is sometimes also referred to as the URL "reference".

Passing an argument of QString() (a null QString) will unset the fragment. Passing an argument of QString("") (an empty but not null QString) will set the fragment to an empty string (as if the original URL had a lone "#").

See also fragment() and hasFragment().

void QUrl::setHost ( const QString & host )

Sets the host of the URL to host. The host is part of the authority.

See also host() and setAuthority().

void QUrl::setIdnWhitelist ( const QStringList & list ) [static]

Sets the whitelist of Top-Level Domains (TLDs) that are allowed to have non-ASCII characters in domains to the value of list.

Qt has comes a default list that contains the Internet top-level domains that have published support for Internationalized Domain Names (IDNs) and rules to guarantee that no deception can happen between similarly-looking characters (such as the Latin lowercase letter 'a' and the Cyrillic equivalent, which in most fonts are visually identical).

This list is periodically maintained, as registrars publish new rules.

This function is provided for those who need to manipulate the list, in order to add or remove a TLD. It is not recommended to change its value for purposes other than testing, as it may expose users to security risks.

This function was introduced in Qt 4.2.

See also idnWhitelist().

void QUrl::setPassword ( const QString & password )

Sets the URL's password to password. The password is part of the user info element in the authority of the URL, as described in setUserInfo().

See also password() and setUserInfo().

void QUrl::setPath ( const QString & path )

Sets the path of the URL to path. The path is the part of the URL that comes after the authority but before the query string.

For non-hierarchical schemes, the path will be everything following the scheme declaration, as in the following example:

See also path().

void QUrl::setPort ( int port )

Sets the port of the URL to port. The port is part of the authority of the URL, as described in setAuthority().

port must be between 0 and 65535 inclusive. Setting the port to -1 indicates that the port is unspecified.

See also port().

void QUrl::setQueryDelimiters ( char valueDelimiter, char pairDelimiter )

Sets the characters used for delimiting between keys and values, and between key-value pairs in the URL's query string. The default value delimiter is '=' and the default pair delimiter is '&'.

valueDelimiter will be used for separating keys from values, and pairDelimiter will be used to separate key-value pairs. Any occurrences of these delimiting characters in the encoded representation of the keys and values of the query string are percent encoded.

If valueDelimiter is set to '-' and pairDelimiter is '/', the above query string would instead be represented like this:

 http://www.example.com/cgi-bin/drawgraph.cgi?type-pie/color-green

Calling this function does not change the delimiters of the current query string. It only affects queryItems(), setQueryItems() and addQueryItems().

void QUrl::setQueryItems ( const QList<QPair<QString, QString> > & query )

Sets the query string of the URL to an encoded version of query. The contents of query are converted to a string internally, each pair delimited by the character returned by pairDelimiter(), and the key and value are delimited by valueDelimiter().

Note: This method does not encode spaces (ASCII 0x20) as plus (+) signs, like HTML forms do. If you need that kind of encoding, you must encode the value yourself and use QUrl::setEncodedQueryItems.

See also setQueryDelimiters(), queryItems(), and setEncodedQueryItems().

void QUrl::setScheme ( const QString & scheme )

Sets the scheme of the URL to scheme. As a scheme can only contain ASCII characters, no conversion or encoding is done on the input.

The scheme describes the type (or protocol) of the URL. It's represented by one or more ASCII characters at the start the URL, and is followed by a ':'. The following example shows a URL where the scheme is "ftp":

The scheme can also be empty, in which case the URL is interpreted as relative.

See also scheme() and isRelative().

void QUrl::setUrl ( const QString & url )

Constructs a URL by parsing the contents of url.

url is assumed to be in unicode format, with no percent encoding.

Calling isValid() will tell whether or not a valid URL was constructed.

See also setEncodedUrl().

void QUrl::setUrl ( const QString & url, ParsingMode parsingMode )

This is an overloaded function.

Parses url using the parsing mode parsingMode.

See also setEncodedUrl().

void QUrl::setUserInfo ( const QString & userInfo )

Sets the user info of the URL to userInfo. The user info is an optional part of the authority of the URL, as described in setAuthority().

The user info consists of a user name and optionally a password, separated by a ':'. If the password is empty, the colon must be omitted. The following example shows a valid user info string:

See also userInfo(), setUserName(), setPassword(), and setAuthority().

void QUrl::setUserName ( const QString & userName )

Sets the URL's user name to userName. The userName is part of the user info element in the authority of the URL, as described in setUserInfo().

See also setEncodedUserName(), userName(), and setUserInfo().

QByteArray QUrl::toAce ( const QString & domain ) [static]

Returns the ASCII Compatible Encoding of the given domain name domain. The result of this function is considered equivalent to domain.

The ASCII-Compatible Encoding (ACE) is defined by RFC 3490, RFC 3491 and RFC 3492. It is part of the Internationalizing Domain Names in Applications (IDNA) specification, which allows for domain names (like "example.com") to be written using international characters.

This function return an empty QByteArra if domain is not a valid hostname. Note, in particular, that IPv6 literals are not valid domain names.

This function was introduced in Qt 4.2.

QByteArray QUrl::toEncoded ( FormattingOptions options = None ) const

Returns the encoded representation of the URL if it's valid; otherwise an empty QByteArray is returned. The output can be customized by passing flags with options.

The user info, path and fragment are all converted to UTF-8, and all non-ASCII characters are then percent encoded. The host name is encoded using Punycode.

QString QUrl::toLocalFile () const

Returns the path of this URL formatted as a local file path.

See also fromLocalFile().

QByteArray QUrl::toPercentEncoding ( const QString & input, const QByteArray & exclude = QByteArray(), const QByteArray & include = QByteArray() ) [static]

Returns an encoded copy of input. input is first converted to UTF-8, and all ASCII-characters that are not in the unreserved group are percent encoded. To prevent characters from being percent encoded pass them to exclude. To force characters to be percent encoded pass them to include.

Unreserved is defined as: ALPHA / DIGIT / "-" / "." / "_" / "~"

 QByteArray ba = QUrl::toPercentEncoding("{a fishy string?}", "{}", "s");
 qDebug(ba.constData());
 // prints "{a fi%73hy %73tring%3F}"

QString QUrl::toString ( FormattingOptions options = None ) const

Returns the human-displayable string representation of the URL. The output can be customized by passing flags with options.

See also FormattingOptions and toEncoded().

QString QUrl::userInfo () const

Returns the user info of the URL, or an empty string if the user info is undefined.

See also setUserInfo().

QString QUrl::userName () const

Returns the user name of the URL if it is defined; otherwise an empty string is returned.

See also setUserName() and encodedUserName().

bool QUrl::operator!= ( const QUrl & url ) const

Returns true if this URL and the given url are not equal; otherwise returns false.

QUrl & QUrl::operator= ( const QUrl & url )

Assigns the specified url to this object.

QUrl & QUrl::operator= ( const QString & url )

Assigns the specified url to this object.

bool QUrl::operator== ( const QUrl & url ) const

Returns true if this URL and the given url are equal; otherwise returns false.

 url = filename; // probably not what you want

 url = QUrl::fromLocalFile(filename);
 url = baseurl.resolved(QUrl(filename));