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pg_lo_read_all Reads an entire large object and send straight to browser


int pg_lo_read_all ( resource $large_object )

pg_lo_read_all() reads a large object and passes it straight through to the browser after sending all pending headers. Mainly intended for sending binary data like images or sound.

To use the large object interface, it is necessary to enclose it within a transaction block.


This function used to be called pg_loreadall().



PostgreSQL large object (LOB) resource, returned by pg_lo_open().

Return Values

Number of bytes read or FALSE on error.


Example #1 pg_lo_read_all() example

('Content-type: image/jpeg');
$image_oid 189762345;
$database pg_connect("dbname=jacarta");
$handle pg_lo_open($database$image_oid"r");

See Also

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User Contributed Notes 2 notes

robert dot bernier5 at sympatico dot ca
12 years ago
// remember, large objects must be obtained from within a transaction
pg_query ($dbconn, "begin");

// "assume" for this example that the large object resource number of the zipped file is "17899"

$lo_oid = 17899;

$handle_lo = pg_lo_open($dbconn,$lo_oid,"r") or die("<h1>Error.. can't get handle</h1>");

//headers to send to the browser before beginning the binary download
header('Accept-Ranges: bytes');
header('Content-Length: 32029974'); //this is the size of the zipped file
header('Keep-Alive: timeout=15, max=100');
header('Content-type: Application/x-zip');
header('Content-Disposition: attachment; filename=""');

pg_lo_read_all($handle_lo) or
  die("<h1>Error, can't read large object.</h1>");

// committing the data transaction
pg_query ($dbconn, "commit");
fabar2 at libero dot it
5 years ago
Pay attention that if you omit the "length" parameter it will read a 8192 bytes object regardless to its real dimensions. If you want to use this function think to save the object size somewhere (usually a field in its table) before reading the object. Alternatively use the pg_lo_readall function.
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