How can I get things from website

jsulm

@victor-wang You can do it like this (Empid= can be just part of the first string - no need for +"Empid=").
Take a look at http://doc.qt.io/qt-5/qstring.html#arg

victor wang

@jsulm @JKSH
I've got another question!
I have 10 different Url wanna connect and get information down.
And i'm using for() to do it.Here is my code.

But it will crash and will not connect to the server.
I assume that it because for() is doing too quick.
So i add this inside the case

reply->isFinished();

But it will crash in the beginning.
What else method can i try or what to fix in my code?
Do i need to add the switch case into replyfinished() slot instead of connect?

Please help!

jsulm

@victor-wang The problem isn't that for loop is too fast (how could it be too fast?).
Starting with case one you have:

reply->isFinished();

How do you initialize reply? Most probably it is not initialized and you're dereferencing dangling pointer.
Second question: why do you call isFinished() on reply? isFinished() is a getter method which you can use to check whether the reply is finished or not. But you do not use its return value, so the call is completely useless.
In general: if your app is crashing you should first debug it before asking in a forum.
So, please remove that useless reply->isFinished(); and debug your code to see where exactly it is crashing and why.

J.Hilk

@victor-wang
To add to @jsulm :

make a make a proper Network function something along the line of:

void getUrlData(QUrl url){
//Do Stuff to call data from one URL
}

Place all your QUrls(10?) into a QList<QUrl>

Now link the IsFinished Signal of your reply to Funktion to call the next URL request from your list.

Dont forget to add a cancel condition, when you reach the end of your list.

Now, start the download chain by calling the first element of your list by hand/button clicked.

victor wang

@J.Hilk
Is that mean that i have to connect IsFinished signal and getUrlData slot in the replyFinished() slot?
What is that mean put in the QList?
There is no IsFinished () signal for reply, just have finished signal.

victor wang

@jsulm
But how can i get 10 times of different Url.
What should i connect signal?

jsulm

@victor-wang What do you mean? You do the same: connect finished() signal to your slot. In that slot (which you already have) you can get the URL from the response to know for which URL this response is coming.
QNetworkAccessManager can handle many requests in parallel - no need to do something special.

victor wang

@jsulm
https://forum.qt.io/topic/77186/how-can-i-get-10-different-url

This is my new topic and i had describe it.
I will describe here for you again.
Please help.

i will send this commend for 10 times in the different CPID.

CPID="TOUCH";
URL="http://192.168.100.59/OLMS/TeskCheck.asp?LSN="+LSN+"&Empid="+EMPID+"&CPID="+CPID+"&CPKey=XXX";
manager->get(QNetworkRequest(QUrl(URL)));

But during the process it will return 500 instead of 200 and can't connect to the Url for the few times.
How can i solve this problem?

jsulm

@victor-wang HTTP 500 status code means: "500 Internal Server Error".
You should check using a browser whether these URLs are working.

victor wang

@jsulm
I'm sure it is worked because if i have just connect that one, it will work correctly.
But if it's in the loop and is not at the first one, sometimes will failed but sometime will success.
So that's why i doubt that because it sending too quick that the server cannot catch it well.

jsulm

@victor-wang Then it is an issue with your server - it is either too slow or it cannot handle concurrent requests.

victor wang

@jsulm
Did you see my code that i had just gave you?

I'm not quite sure that is the server issue.
I doubt that my code is not really perfect.
Could you help me see the code?

jsulm

@victor-wang Your do..while loop is an infinite loop if you get a response != 200
It does not make sense as a reply is either 200 or not: it will not become 200 if it wasn't before by some magic, so remove that loop.
As I said 500 means internal server error. You get a connection but the server fails to do what it is expected to do and sends 500 back.
If you want to slow down your requests you can use QTimer.

victor wang

@jsulm

If i change my code like this.

It will failed for a few times.

I'm trying to solve this kind of problem

jsulm

@victor-wang What does fail mean? Do you get 500?

jsulm

@victor-wang If you do not want to send all request in parallel you can do it one after another.

victor wang

@jsulm
Yes, it will show 500.

how to do that?
Could you teach me?

Or can i do 5 times and another 5 times.

jsulm

@victor-wang Put all URLs you want to get in a list.
Write a method which takes next URL from that list and sends a request.
Call this method in your button slot.
In the finished() slot you call this method again after handling current response if the list is not empty.

victor wang

@jsulm
Sorry it is too abstract for me,
Did you have an example?

jsulm

@victor-wang No, I don't have an example.
What is abstract here? I gave you a quite complete description.
What exactly is not clear?