TCPDF ERROR: Some data has already been output, can't send PDF file

Question

I keep receiving this error when trying to add my own array into the code. Here is my array;

$array = array();

while (odbc_fetch_row($rs))
{
    $array[] = odbc_result($rs,'Product Name');
}
 
$test = print_r($array);

The original code is here. I'm using an example page to try it because I know the example page works fine.

http://www.tcpdf.org/examples/example_001.phps

This code is before the $html variable and when it is set I just add the $test variable into the $html variable. The odbc connection works fine and the example works fine before I add any code but when I run the script I get this error;

Array ( [0] => Test1 [1] => Test2 ) TCPDF ERROR: Some data has already been output, can't send PDF file

And there is also more than 2 items in the Array. Any ideas?

Was there any outbut before headers were sent? Is it UTF-8 file? Is it UTF-8 without BOM file? — BlitZ, Apr 15 '13 at 08:47
have tried changing the variable names of `$test` and `$array`? — Mark, Apr 15 '13 at 08:47
You get this error because you want to print out something before the pdf headers are sent, comment the pdf part for debug and then use them — ka_lin, Apr 15 '13 at 08:48
If you want to have the return value of [`print_r`](http://php.net/print_r) you need the second parameter: `$test = print_r($array, true);` — dan-lee, Apr 15 '13 at 08:48
Hi @CORRUPT I'm not sure exactly what you mean about the headers, There shouldent be any output because I have put the $test variable into the Code that generates the HTML part, I believe it is UTF-8 — Alex, Apr 15 '13 at 08:51
I added the true parameter and it has worked! Thank you @DanLee for your help. Thank you all for your help and comments! — Alex, Apr 15 '13 at 08:53

score 54 · Answer 1 · answered Mar 11 '16 at 23:06

54

Add the function ob_end_clean(); before call the Output function. It worked for me within a custom Wordpress function!

ob_end_clean();
$pdf->Output($pdf_name, 'I');

answered Mar 11 '16 at 23:06

Fab

1,080
12
19

score 40 · Answer 2 · answered Jan 15 '14 at 06:10

40

Just use ob_start(); at the top of the page.

answered Jan 15 '14 at 06:10

vishal jaura

409
4
3

score 10 · Answer 3 · answered Jun 17 '14 at 02:06

10

Add the function ob_end_clean() before call the Output function.

answered Jun 17 '14 at 02:06

user2928471

136
1
5

I have a pdf generator that works fine in some server or fire errors in others, nothing clear because I have no white spaces at beginning or just after `Output($data, 'D')` everything works fine. – Farid Mar 17 '23 at 20:03

score 9 · Answer 4 · answered Jun 25 '15 at 03:48

9

I just want to add that I was getting this error, and nothing would fix it until I changed the Output destination parameter from F to FI. In other words, I have to output to both file and inline.

Output('doc.pdf', 'I')

to

Output('doc.pdf', 'FI')

I have no idea why this made the difference, but it fixed the error for me...

answered Jun 25 '15 at 03:48

Black

5,023
6
63
92

Yes ! Worked with php7.0.10 and Html2PDF 4.03 – gael Apr 25 '19 at 03:24

score 6 · Answer 5 · answered Dec 03 '13 at 20:32

6

This problem means you have headers. Deletes tags

?>

at the end of your code and make sure not to have whitespace at the beginning.

answered Dec 03 '13 at 20:32

Javier Claros

349
4
6

it means, content has already been sent. So the headers cannot be set anymore – Ibu Dec 03 '13 at 20:51

Clark Superman · Answer 6 · 2014-04-25T11:31:25.330

The tcpdf file that causes the "data has already been output" is in the tcpdf folder called tcpdf.php. You can modify it:

add the line ob_end_clean(); as below (3rd last line):

public function Output($name='doc.pdf', $dest='I') {
    //LOTS OF CODE HERE....}
    switch($dest) {
        case 'I': {
        // Send PDF to the standard output
        if (ob_get_contents()) {
        $this->Error('Some data has already been output, can\'t send PDF file');}
        //some code here....}
            case 'D': {         // download PDF as file
        if (ob_get_contents()) {
    $this->Error('Some data has already been output, can\'t send PDF file');}
            break;}
        case 'F':
        case 'FI':
        case 'FD': {
            // save PDF to a local file
                 //LOTS OF CODE HERE.....       break;}
        case 'E': {
            // return PDF as base64 mime email attachment)
        case 'S': {
            // returns PDF as a string
            return $this->getBuffer();
        }
        default: {
            $this->Error('Incorrect output destination: '.$dest);
        }
    }
           ob_end_clean(); //add this line here 
    return '';
}

Now lets look at your code.
I see you have $rs and $sql mixed up. These are 2 different things working together.

$conn=odbc_connect('northwind','****','*****');
if (!$conn) {
   exit("Connection Failed: " . $conn);
 }

$sql="SELECT * FROM products"; //is products your table name?
$rs=odbc_exec($conn,$sql);
if (!$rs) {
  exit("Error in SQL");
}

while (odbc_fetch_row($rs)) {
  $prodname=odbc_result($rs,"Product Name"); //but preferably never use spaces for table names.
 $prodid=odbc_result($rs,"ProdID");  //prodID is assumed attribute
  echo "$prodname";
  echo "$prodid";
}
odbc_close($conn);

now you can use the $prodname and output it to the TCPDF output.

and I assume your are connecting to a MS access database.

score 4 · Answer 7 · answered Dec 20 '18 at 19:56

4

Use ob_start(); at the beginning of your code.

answered Dec 20 '18 at 19:56

Dipanshu Chaubey

880
1
9
18

score 2 · Answer 8 · answered Dec 08 '15 at 13:45

2

for my case Footer method was having malformed html code (missing td) causing error on osx.

public function Footer() {
$this->SetY(-40);
$html = <<<EOD
<table>
<tr>
 Test Data
</tr>
</table>
EOD;
$this->writeHTML($html);
}

answered Dec 08 '15 at 13:45

ranjeetcao

1,743
2
20
28

him · Answer 9 · 2018-10-22T03:53:36.780

2

use ob_end_clean();

$pdf->Output($file, 'I'); to open pdf. It works for me

edited Oct 22 '18 at 03:53

answered Jun 23 '16 at 10:23

him

3,325
3
14
17

score 2 · Answer 10 · answered Aug 01 '17 at 10:36

I had this but unlike the OP I couldn't see any output before the TCPDF error message.

Turns out there was a UTF8 BOM (byte-order-mark) at the very start of my script, before the <?php tag so before I had any chance to call ob_start(). And there was also a UTF8 BOM before the TCPDF error message.

score 2 · Answer 11 · answered Nov 29 '17 at 06:27

2

I had this weird error and the culprit is a white space on the beginning of the PHP open tag

even without the ob_flush and ob_end_clean

Just make sure there are no extra white spaces on or after any <?php ?> block

answered Nov 29 '17 at 06:27

tomexsans

4,454
4
33
49

score 2 · Answer 12 · answered Nov 14 '18 at 01:01

I had the same error but finally I solved it by suppressing PHP errors Just put this code error_reporting(0); at the top of your print page

    <?php 
    error_reporting(0); //hide php errors
    if( ! defined('BASEPATH')) exit('No direct script access allowed');
    require_once dirname(__FILE__) . '/tohtml/tcpdf/tcpdf.php';
    .... //continue

score 2 · Answer 13 · answered Mar 04 '20 at 07:13

The error of "Some data has already been output, can't send PDF file" refers to the output buffer of PHP.

so you need to clean any content of the output buffer before sending output.

ob_end_clean(); // Clean any content of the output buffer

then

$pdf->Output('example_001.pdf', 'I'); // Send the PDF !

score 1 · Answer 14 · edited Oct 09 '17 at 13:24

1

This problem is when apache/php show errors.

This data(html) destroy pdf output.

You must off display errors in php.ini.

edited Oct 09 '17 at 13:24

Regolith

2,944
9
33
50

answered Oct 09 '17 at 10:49

Maykel

11
2

score 1 · Answer 15 · edited May 21 '19 at 20:12

1

For those who are still facing this issue try adding:

libxml_use_internal_errors(true);

before the loadHtml call and add

libxml_use_internal_errors(false);

after the call.

This solved it for me.

edited May 21 '19 at 20:12

Guilherme Nastrini

28
5

answered Sep 26 '18 at 13:21

S.Simkhada

116
1
2
13

Which loadHtml call? – Russell G Oct 15 '20 at 13:56

TCPDF ERROR: Some data has already been output, can't send PDF file

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