QFtp list()

[magguz]

Hi,

I'm using QFtp to get the contents of a directory on a FTP-Server. For this I want use the method list(). But it doesn't work. How I must use the method to get the contents of a directory?

[SGaist]

Hi,

How are you using it ?

[mrjj]

Hi
Are you using the commandFinished signal ?
list() is async.

[magguz]

@mrjj said in QFtp list():

Hi
Are you using the commandFinished signal ?
list() is async.

No. In which way I must use this signal?

[mrjj]

@magguz
Like any other signal.
Connect it to your slot.
http://blackberry.github.io/Qt2Cascades-Samples/docs/qftp.html

[magguz]

@mrjj said in QFtp list():

@magguz
Like any other signal.
Connect it to your slot.
http://blackberry.github.io/Qt2Cascades-Samples/docs/qftp.html

Hi,

I have tried this now:

ftp = new QFtp();
    ftp->connectToHost("ftp.example.com");
    ftp->login("","");
    ftp->list();
    connect(ftp, SIGNAL(commandFinished(int,bool)), this, SLOT(ftpCommandFinished()));

The method connect seems to work. It calls ftpCommandFinished(). Inside ftpCommandFinished() I wrote this to set the text of a QTextEdit:

ui->textEdit->append(ftp.list());

But this causes an error. What does I make wrong?

[mrjj]

Hi

But this causes an error. What does I make wrong?

First step is to show the actual error :)

also
the slot seems wrong. should have int and bool too
connect(ftp, SIGNAL(commandFinished(int,bool)), this, SLOT(ftpCommandFinished(int,bool)));

[magguz]

@mrjj said in QFtp list():

Hi

But this causes an error. What does I make wrong?

First step is to show the actual error :)

This error occurs:

invalid user-defined conversion from 'int' to 'const QString&' [-fpermissive]
ui->textEdit->append(m_ftp->list());

[mrjj]

@magguz
Hi
it says "why you give me int when i want qstring"
what does list() return ?

[magguz]

@mrjj

I tried

cout << ftp->list();

and now it gives integers back

[mrjj]

@magguz
Hi
you really have to read docs as else it wont work for you :)
http://doc.qt.io/archives/qt-4.8/qftp.html#list

int QFtp::list(const QString & dir = QString())
Lists the contents of directory dir on the FTP server. If dir is empty, it lists the contents of the current directory.

The listInfo() signal is emitted for each directory entry found.

The function does not block and returns immediately. The command is scheduled, and its execution is performed asynchronously. **The function returns a unique identifier which is passed by commandStarted() and commandFinished().**

When the command is started the commandStarted() signal is emitted. When it is finished the commandFinished() signal is emitted.

so it returns an unique identifier not a list. and it will send a signal listInfo() for each directory it finds.
so its not like you call one function and get answer back at once.
the operation is asynchronously. (if u dont know that means , please ask)
its critical for understanding. :)

[magguz]

@mrjj

Sorry, but I'm a beginner in C++/Qt. How I must handle the unique identifier that is returned? And what I must specify for "const QString" as the first parameter of QFtp::list?

[mrjj]

@magguz
Hi
Dont be sorry. just practice reading docs. Its a must do for becoming PRO. :)
It was not meant as lifted finger. just that u really need it :)

The ID is just used to know what command a response belongs to.
when command is done, it calls
void QFtp::commandFinished(int id, bool error)

so here the ID will be the same as the list() returns.

so if you have issued multiple commands, that way you know what is what.

The "const QString" is the name of a directory. but if you leave it empty, docs says it just mean
"root"/top folder then. So if you dont need to only process a certain subfolder, i think leaving it empty is fine.

[magguz]

@mrjj

And how I can get the content of a directory on a FTP-server as a string?

[mrjj]

@magguz
for each file it will send event listInfo() signal so you need to connect to that and build a string yourself if you want
that.
void QFtp::listInfo(const QUrlInfo & i)

so you get a QUrlInfo pr file.
you can ask for string with
QString QUrlInfo::name() const

"The listInfo() signal is emitted for each directory entry found."

[magguz]

@mrjj

I have now created a second connect method and a function "addToList()" like this:

connect(m_ftp, SIGNAL(listInfo()), this, SLOT(addToList()));

and now?

[mrjj]

@magguz
HGi
its :listInfo(const QUrlInfo & i)
so syntax is not correct

connect(m_ftp, SIGNAL(listInfo(const QUrlInfo &), this, SLOT(addToList(const QUrlInfo &));
and change addToList so it takes that parameter.
For each file it calls it
and you can build your list or what you need.

[magguz]

@mrjj said in QFtp list():

@magguz

and change addToList so it takes that parameter.

how I can take the parameter into the addToList function?

[mrjj]

@magguz
just change the addToList so it the real slot have a variable name.
(not in the connect. they are always without names)

void addToList(const QUrlInfo & file);

[magguz]

@mrjj

I changed the addToList() to addToList(const QUrlInfo & file)
Now I get an object named "file" for every directory entry, right?

[mrjj]

@magguz
yes you get an URL object for each file
and the (QUrlInfo) file has a function called
name() that returns a QString.

http://doc.qt.io/archives/qt-4.8/qurlinfo.html

[magguz]

@mrjj

now I want to append the strings to a textEdit like this:

ui->textEdit->append(file.name());

but it doesn't work

[mrjj]

@magguz
in what way "doesn't work" ?
What does it append?
is the addToList called ?

[magguz]

@mrjj said in QFtp list():

@magguz
in what way "doesn't work" ?
What does it append?
is the addToList called ?

no it seems that addToList is not called. It appends nothing.

[mrjj]

@magguz
well check all your connects like
qDebug() << "status:" << connect(xxxx); // xxxx being what u have
and see they return true.
also test that it does connect to the server. check errors and such.

[magguz]

@mrjj

I found what was wrong. I changed

ftp->login("","");

in

ftp->login();

and it works. Thanks for your help!

[magguz]

There is still one thing: In the TextEdit he lists all entries sixteen times

[mrjj]

@magguz
Hi
well
what does file.name() contains ?
in
ui->textEdit->append(file.name());

I cant guess , please debug it using the debugger so you can see what happens.

[magguz]

@mrjj

I changed the connect statements like this:

connect(ftp, SIGNAL(listInfo(const QUrlInfo &)), this, SLOT(addToList(const QUrlInfo &)), Qt::UniqueConnection);

I added only Qt::UniqueConnection as parameter. Now everything is fine :-)

[mrjj]

@magguz
Ahh, you might have added the connect many times :)
well UniqueConnection solves also :)