PHP string concatenation error. Can anyone correct it?

Question

Can someone tell me what is wrong with my code?

        $c =  '<div class="desc">';
    if( $_POST['login_post'] == '1') { 
    $username = $_POST['user_login'];
    $password = $_POST['password'];
        $message = log_in_user($username, $password);
    }
    display_message($message); 
    $c .= '<form name="loginform" id="loginform" method="post" action="">
                            <label>Username:</label>
                            <div><input type="text" name="user_login" id="user_username"  value="" size="20"  maxlength="40" tabindex="10" /></div>
                            </div>
                            <div class="group">
                            <label>Password:</label>
                            <div><input type="password" name="password" id="user_password"  value="" size="20"  maxlength="40" tabindex="20" /></div>
                            </div>
                             <input type="hidden" name="login_post" value="1"/>

                            <div class="group">
                            <label></label>
                            <div><input type="submit" name="submit" id="submit" class="bluebutton" value="Log In Now" /><span class="forgotlink"><a href="/forgot-password/">Forgot your password?</a></span></div>
                            </div> 
                </form>

                    </div>';
    $c = str_replace('%value%',5,$c);
    return $c;

That display_message($message); function is supposed to display the message inside the desc div. Instead, it is displaying above (outside) the desc div.

Am I concatenating PHP code incorrectly? If yes, can some one correct me? Thanks!

Update:

Here is my display_message function:

function display_message( $message = false ) {
    if( is_wp_error( $message ) ) {
        echo '<div class="errorMessage"><p>' . $message->get_error_message() . '</p></div>';    
    }
    elseif ($message != '') {
        echo '<div class="successMessage"><p>' . $message . '</p></div>';   
    }
}

Does display_message() return a value, or does it simply have an echo within the function itself? — Mark Baker
– Mark Baker, Commented Mar 24, 2012 at 21:54
@MarkBaker I updated my display_message function code in the question. Please check it — Giri
– Giri, Commented Mar 24, 2012 at 22:02

Joachim Isaksson · Accepted Answer · 2012-03-24 22:26:32Z

2

display_message() will print out the message instead of concatenating it. Try changing display_message($message); to $c .= htmlspecialchars($message); and it should end up inside the div as it is supposed to.

Edit: Since display_message does more than just display the message, it needs to be rewritten slightly;

function format_message( $message = false ) {
    if( is_wp_error( $message ) ) {
        return '<div class="errorMessage"><p>' . $message->get_error_message() . '</p></div>';    
    }
    elseif ($message != '') {
        return '<div class="successMessage"><p>' . $message . '</p></div>';   
    }
}

and the concatenation should instead be;

$c .= format_message($message);

edited Mar 24, 2012 at 22:26

answered Mar 24, 2012 at 21:53

Joachim Isaksson

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7 Comments

jeroen Over a year ago

That is not going to work if display_message() prints or echoes something.

Giri Over a year ago

@jeroen Yes my display_message echoes messages. I updated the question with my display_message function

Joachim Isaksson Over a year ago

@user1091558 Updated my answer with the new info.

Giri Over a year ago

@JoachimIsaksson Thanks for your answer. That display message function also used by some other pages. But string concatenation requires only for my login page. If i change display_message function won't it affect other pages which uses that function?

Joachim Isaksson Over a year ago

@user1091558 That's why I made it into a new format_message() function so it wouldn't affect other pages. You could make display_message into just an echo format_message($message) if you decide to go this way and want to eliminate some code.

|

Taha Paksu · Accepted Answer · 2012-03-24 21:57:03Z

try loading the login result into another variable, then displaying it, after that concenating it to $message.

$c =  '<div class="desc">';
if( $_POST['login_post'] == '1') { 
$username = $_POST['user_login'];
$password = $_POST['password'];
    $login_message = log_in_user($username, $password);
}
display_message($login_message); 
$c .= $login_message . '<form name="loginform" id="loginform" method="post" action="">
                        <label>Username:</label>
                        <div><input type="text" name="user_login" id="user_username"  value="" size="20"  maxlength="40" tabindex="10" /></div>
                        </div>
                        <div class="group">
                        <label>Password:</label>
                        <div><input type="password" name="password" id="user_password"  value="" size="20"  maxlength="40" tabindex="20" /></div>
                        </div>
                         <input type="hidden" name="login_post" value="1"/>

                        <div class="group">
                        <label></label>
                        <div><input type="submit" name="submit" id="submit" class="bluebutton" value="Log In Now" /><span class="forgotlink"><a href="/forgot-password/">Forgot your password?</a></span></div>
                        </div> 
            </form>

                </div>';
$c = str_replace('%value%',5,$c);
return $c;

jeroen · Accepted Answer · 2012-03-24 22:11:50Z

1

If your function display_message() echoes something, you need to use output buffering to capture the result and add it to your $c variable. Otherwise it gets echoed right away.

Edit: With output buffering:

ob_start();
display_message($message); 
$c .= ob_get_contents();            // adding output to the variable
ob_end_clean();

A better option would probably be to have display_message() return a string and add that string to $c.

Based on your edit, I would just change the function to:

function display_message( $message = false ) {
    if( is_wp_error( $message ) ) {
        return '<div class="errorMessage"><p>' . $message->get_error_message() . '</p></div>';    
    }
    elseif ($message != '') {
        return '<div class="successMessage"><p>' . $message . '</p></div>';   
    }
    return NULL;
}

and do:

$c .= display_message($message);

edited Mar 24, 2012 at 22:11

answered Mar 24, 2012 at 21:54

jeroen

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2 Comments

Giri Over a year ago

Thanks for your answer jeroen. But that display message function also used by some other pages. But string concatenation requires only for my login page. If i change display_message function won't it affect other pages which uses that function?

jeroen Over a year ago

@user1091558 Yes it would. In that case you would have to use output buffering to capture the result and avoid it gets echoed right away. I'll add a simple example.

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