ibase_blob_get()

(PHP 5, PHP 7)

Get len bytes data from open blob

说明

ibase_blob_get(resource $blob_handle,int $len): string

This function returns at most$lenbytes from a BLOB that has been opened for reading by ibase_blob_open().

Note:

It is not possible to read from a BLOB that has been opened for writing by ibase_blob_create().

参数

$blob_handle

A BLOB handle opened with ibase_blob_open().

$len

Size of returned data.

返回值

Returns at most$lenbytes from the BLOB, or FALSE on failure.

范例

Example #1 ibase_blob_get() example

<?php
$result    = ibase_query("SELECT blob_value FROM table");
$data      = ibase_fetch_object($result);
$blob_data = ibase_blob_info($data->BLOB_VALUE);
$blob_hndl = ibase_blob_open($data->BLOB_VALUE);
echo         ibase_blob_get($blob_hndl, $blob_data[0]);
?>

参见

• ibase_blob_open()Open blob for retrieving data parts
• ibase_blob_close()Close blob
• ibase_blob_echo()Output blob contents to browser

The first example is wrong, is missing ibase_blob_close() function.
The correct example is :
<?php
  $sql   = "SELECT blob_value FROM table";
  $result  = ibase_query($sql);
  $data   = ibase_fetch_object($result);
  $blob_data = ibase_blob_info($data->BLOB_VALUE);
  $blob_hndl = ibase_blob_open($data->BLOB_VALUE);
  print    ibase_blob_get($blob_hndl, $blob_data[0]);
  // without close blob conection, php and ibase_blob_get() do not run.
 ibase_blob_close($blob_hndl); 
?>

I found examples like these:
$sql = "SELECT ID, CONTENTTYPE, BLOBSIZE, DATA,NAME ";
$sql.= " FROM OM_BLOB WHERE ID = 42";
$result = ibase_query($sql);
while ($row=ibase_fetch_object($result))
{
  $blob_data = ibase_blob_info( $row->DATA);
  $blob_hndl = ibase_blob_open($row->DATA);
  $image = ibase_blob_get( $blob_hndl, $blob_data[0]);
}
but this won't work for large blobs.
One solution for big blobs is to retrieve them by chunks:
$sql = "SELECT ID, CONTENTTYPE, BLOBSIZE, DATA,NAME ";
$sql.= " FROM OM_BLOB WHERE ID = 42";
$result = ibase_query($sql);
while ($row=ibase_fetch_object($result))
{
  $image = ibase_blob_get($blob_hndl,8192);
  while($data = ibase_blob_get($blob_hndl, 8192)){ 
    $image .= $data; 
  }
}

The ways mentioned above won't work with segmented blobs. To fix this, I use the following:
(btw, $result->MFOTO is an image in the database)
<?php
  $result = ibase_fetch_object($result);
  
  /*
   ibase_blob_info array: 
   [0] bloblength(total)
   [1] number of segments
   [2] size of largest segment
   [3] stream or segmented blob
   [4] ??
  */
  $blobinfo = ibase_blob_info($result->MFOTO); 
  
  $blobhandle = ibase_blob_open($result->MFOTO);
  for($i = 0; $i < $blobinfo[1]; $i++){
    $readsize = $blobinfo[2];
    if($i == ($blobinfo[1] - 1)){
      $readsize = $blobinfo[0] - (($blobinfo[1] - 1) * $blobinfo[2]);
    }
    $totalimage .= ibase_blob_get($blobhandle, $readsize);
  }
  ibase_blob_close($blobhandle);
  echo $totalimage; 
?>
This should do the trick ;)