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问题:

I am developing the client side of a web application in iOS/Swift, and right now I am testing the part that communicates with the server. I setup a basic website on localhost at:

http://localhost/~username/ConnectivityTest/login

(which corresponds to /Users/username/Sites/ConnectivityTest/login on my Mac's file system).

The server side script (index.php on the directory above) is:

<?PHP
    $userId   = $_POST["userId"];
    $password = $_POST["password"];

    if (empty($userId) || empty($password)){

        echo "Error: empty post variables";
    }
    else{
        // Process credentials...

I am using the NSURLSession API on iOS, but I noticed that no matter how I configure my requests, even though the connection succeeds (i.e., returns an http code of 200 and the response body as data), the POST variables are unavailable (empty) on the server side.

So I decided to try sending the request manually using Postman on the browser (to try to rule out any mistakes on my iOS/Swift code), but I don't know how I should configure it (I am not versed in HTTP, it all is still a bit confusing to me):

Should I set the Content-Type header to application/json, application/x-www-form-urlencoded, or what?
Should I send the body data as form-data, x-www-form-urlencoded or raw?

In Postman, I set the body data (raw) as follows:

{
    "userId":"my-user-name",
    "password":"123456"
}

Alternativley, as form-data, it is:

userId     my-user-name      [Text]
password   12345             [Text]

As x-www-form-urlencoded, it is:

userId     my-user-name      
password   12345

Everything I try gives me the response "Error: empty post variables" that I set in my code's error path (i.e., $_POST['userId'] or $_POST['password'] are empty).

If, instead, I pass the variables as URL parameters:

http://localhost/~username/ConnectivityTest/login/index.php?userId=my-user-name&password=12345

...and access them in the script as &_GET['userId'] and $_GET['password'], it works fine.

what am I missing?

UPDATE: I created an HTML file in the same directory as the php file:

<html>
    <body>
        <form action="index.php" method="post">
            User name: <input type="text" name="userId"><br>
                Password: <input type="text" name="password"><br>
                    <input type="submit" value="Submit">
        </form>
    </body>
</html>

If I load the above page in a browser, fill in the fields and submit the form, the $_POST variables on my php script get the correct values. So the php code is correct, and I am setting up my request wrong in Postman (still don't know why).

UPDATE 2: Just in case there was a problem with localhost, I moved the script to a shared wb hosting service that I control, but the result is the same.

UPDATE 3: I must have missed it somehow before, but there is ONE setup that I got working:

Headers: Content-Type application/x-www-form-urlencoded

Body ("raw"): userId=my-user-name&password=123456

However, this restricts me to flat lists of key/value; If I wish to send more structured (i.e., nested) data to the server I need JSON support...

回答1:

After searching here and there, I discovered that the post body data gets into the $_POST variables only when you send them as a form -i.e., application/x-www-form-urlencoded- (I guess that is what $_POST stands for, not the method used for the request). Correct me if I'm saying something that isn't correct.

When using a Content-Type of application/json, code like the following does the trick:

$data = json_decode(file_get_contents('php://input'), true);

$userId = $data["userId"];
$password = $data["password"];

I guess this is very basic stuff, but then again, my knowledge of HTTP is very limited...

回答2:

A mistake I made when first using Postman was setting the params when using the POST method which would fail. I tried your Update 3 which worked and then I realized there were key value pairs in the Body tab.

Removing the params, setting the Body to "x-www-form-urlencoded" and adding the variables to be posted here works as expected.

My oversight was I figured there would be a single section to enter the values and the method would determine how to pass them along which makes sense in case you would like to send some parameters in the URL with the POST

回答3:

Comment by @FirstOne saved me. I added a forward slash to the URL and it solved the problem. This way, my php script could detect the request as POST even without setting header to

Content-Type application/x-www-form- urlencoded

I also tested my code without a header and it works fine. I tested with Content-type: application/json too and it works fine.

if($_SERVER['REQUEST_METHOD] = 'POST') { echo 'Request is post'; }

My script returned 'Request is post' using RESTEasy - Rest client on Chrome. Thanks, FirstOne.