PHP MYSQL BLOB导出为csv格式

Question

I am trying to create a script that can export data from a mysql database containing files (pdf mainly). This data is then imported onto the local version of the system.

However I have a problem with the BLOB field, when I export and import using PHPMYADMIN, it works fine, however when using my script, the BLOB field has additional code added to the top. Almost as if it is code to instruct programs how to deal with it. When i try to import this version into PHPMYADMIN, it doesnt work.

Is is a formatting error, do i need to convert it to a type. At present it is simply pulled from the database as a row['content'] item and then outputted to the csv

Any help would be much appreciated

Regards

///////////////// source code of my script

$file = 'supportingFiles'; // csv name.
$result = mysql_query("SHOW COLUMNS FROM files");
$a = 0;

if (mysql_num_rows($result) > 0) {                                      //print column titles based on number of columns in the two files
while ($row = mysql_fetch_assoc($result)) {
$a++;
}
}

$values = mysql_query("SELECT * FROM files ");          //select client details wehere required

while ($rows = mysql_fetch_array($values)) {                                        //print client information
for ($k=0;$k<$a;$k++) {

$csv_output .= $rows[$k].",";
}
$csv_output .= "\n";            //end of line
}

$filename = $file."_".date("d-m-Y_H-i",time());

header("Content-type: application/csv");
header("Content-disposition: csv" . date("Y-m-d") . ".csv");
header( "Content-disposition: filename=supportingFiles.csv");

echo $csv_output;           //output data file

when an export is ran using this script the following proceeds the actual content outputted when a csv export of the table is run from phpmyadmin...

%âãÏÓ
%%ISIS AfpToPdf-V.6.2/h3 '2008-05-19 (build:6.20.0.08205)'
4 0 obj
[
/DeviceRGB
]
endobj
5 0 obj
[/Pattern 4 0 R] 
endobj
6 0 obj
[
/DeviceCMYK
]
endobj
7 0 obj
[/Pattern 6 0 R] 
endobj
14 0 obj
<</Length 1221/Filter/FlateDecode>>
stream
xÚ•WÛnã6ýÿümÌ%)’¢úo6Š6Û„ûTÈckW–RYÎ6ýüh‡CJ¶Ûi€\à™áp.gÇ‹|Æ!ÿ6{wÃA@~‚ãçgø3Í    %ph×3ü^ïÿæ[P2cB‚É4Käw?
R<¦èØo-\ïðs³_oüqŽ.yL11°Ø·uåžà}ÕìÜTûáÏüã-\-ó©.ÿ„ÅŸ^þ!Ÿý=óõ‘YÆRƒ=±ÌÀ¬Á$´îÊ”)•TÉ   ±6a¶×JŸúXËY¦ÇJµÖ²äìQ«/]k&ÍyÇœyV›¦gµši{^›0c†¨\c-jÏÆlì!ªÚQ!    Íä^#YrÁóQ™_juÊ5x¶“˜µaâÂYÉôùZ)ëQÛk³ÉY•2~>_¥Ž1×{þ4[ä’ŒÉÅv2<¾ÿâ{Œ_ïªr…ŒžÂð©©„9øú™FFÄZÄ«ª†1Ö        ŒÎ’58Tj˜â‡$áb¯D`²H‡¾
üí</m›ºÛ|¿ƒÕ¦h×n²ã¯—ˆøQc¿¼Ç‰ãvûå·ê k<ÙyJ+¦
"2¦75^‚Ó ãg&x M„ñ4–êØå  wÈ°\äå%BÄËØŒ4쉷è÷çßASÃsb¢ñ(¾t_bO¼Gî…›7]Qõe„û¦=ªo:9ø|   Ö”3¾2õØéPü74–š 2qÔYle%Ûn‹ö š{xjö-«U³¯»·5Wáhz‹ª¨Wˆ¿¶ÙÂCëËf¿ƒeœ¥ Ÿ”Ã\{IÆðE   9i=î…    ð3ŠŠß‹§­«;DõÊ•îî¸  4ñþYöóÓÎ^¯<ÁeN$…ö±öG    ¥§÷kÔå”^]¥Xò2¼cˆ}\>¢LdQÅSA7=6RN¾‘¥B—    dXêjë[w{z¿Uâ‡WIÈxVÊK¥`ܬpЗֈx—þ! U¦¨¿ús    ½%ÁBŒœãÃ%؃ï¤ïž«p†ËzMÁaÞ6Ê»†"
iç\lMÏ>ÈL®v‘€šû8ê:Ú<kwh
‰h¶l#ì†ý"ô·+ÊjÇN½ü§7\2¥éû=0å‹¡¾ô½&±HW´ƒ„J^…–ǯ"?

Answer 1

that is because CSV is not well standardized as a format (not even the "comma" as in "comma seperated values") and it is because phpmyadmin does some encoding/decoding on the values when exporting/importing.

You need this encoding/decoding part, because your binary BLOB (as you said, mostly PDF) can easily contain commas, line breaks, quotes, and all kinds of stuff that breaks a CSV parser.

To import your files using phpmyadmin, you would have to replicate the encoding machanism used there - lucky you that it's open source and you can have a look at the code .

Alternatively, if you want your own export/import mechanism (lets say: you write your own importer that matches your exporter) then you could make good use of base64 encoding here to ensure your CSV (which is intended as a plain-text format by the way) stores binary data correctly.

exporter:

// convert binary blob to text format
$plaintextdata_for_csv = base64_encode($binarydata_from_blob); 

importer:

// decode text format to binary blob
$binarydata_for_blob = base64_decode($plaintextdata_from_csv);