NodeJS write binary buffer into a file

Question

I can't rewrite a file that I am getting from a binary buffer, I have checked with the original file and all bytes are the same.

This is the file create from NodeJS:

# hd test.txt  | head 00000000  47 49 46 38 39 61 32 00  32 00 f7 00 00 96 8c 73  |GIF89a2.2.�....s| 00000010  66 5e 45 c6 bb 9f 7b 72  5a 47 47 47 8a 81 65 ca  |f^Eƻ.{rZGGG..e�| 00000020  c1 a6 c9 c1 ac ee ea dd  c8 c5 bc 8c 87 7a d3 c9  |���������ż..z��| 00000030  ab 43 3b 26 eb e5 d1 fa  fa fa e5 e4 e2 a6 9d 83  |�C;&����������..| 00000040  86 7e 67 c1 b4 8e e4 dc  c6 82 82 82 e1 dd d1 e3  |.~g��.���...����| 00000050  dd ca e4 da bc f5 f1 e6  26 25 25 9c 91 73 f8 f3  |���ڼ���&%%..s��| 00000060  e4 c3 b9 9d d3 ca b4 4a  42 2a d1 c6 a2 6c 62 46  |�ù.�ʴJB*�ƢlbF| 00000070  ea e6 db bb b3 9c db d3  bb 5c 54 3d f1 ee e6 dc  |��ۻ�.�ӻ\T=����| 00000080  da d3 e7 e4 dc ce c2 9f  f8 f6 f2 76 6c 53 fc fb  |�������.���vlS��| 00000090  f9 e9 e1 ca 17 13 09 67  4d 00 f8 f4 e8 dc d3 b5  |����...gM.����ӵ| 

This the original one:

$ hd runner_small.gif   | head 00000000  47 49 46 38 39 61 32 00  32 00 f7 00 00 96 8c 73  |GIF89a2.2......s| 00000010  66 5e 45 c6 bb 9f 7b 72  5a 47 47 47 8a 81 65 ca  |f^E...{rZGGG..e.| 00000020  c1 a6 c9 c1 ac ee ea dd  c8 c5 bc 8c 87 7a d3 c9  |.............z..| 00000030  ab 43 3b 26 eb e5 d1 fa  fa fa e5 e4 e2 a6 9d 83  |.C;&............| 00000040  86 7e 67 c1 b4 8e e4 dc  c6 82 82 82 e1 dd d1 e3  |.~g.............| 00000050  dd ca e4 da bc f5 f1 e6  26 25 25 9c 91 73 f8 f3  |........&%%..s..| 00000060  e4 c3 b9 9d d3 ca b4 4a  42 2a d1 c6 a2 6c 62 46  |.......JB*...lbF| 00000070  ea e6 db bb b3 9c db d3  bb 5c 54 3d f1 ee e6 dc  |.........\T=....| 00000080  da d3 e7 e4 dc ce c2 9f  f8 f6 f2 76 6c 53 fc fb  |...........vlS..| 00000090  f9 e9 e1 ca 17 13 09 67  4d 00 f8 f4 e8 dc d3 b5  |.......gM.......| 

You can compare these two files and every bytes are the same, I am guessing that the encoding from NodeJS is not the right one.

This is the piece of code

var foo = "71%73%70%56%57%97%50%0%50%0%247%0%0%150%140%115%102%94%69%198%187%159%123%114%90%71%71%71%138%129%101%202%193%166%201%193%172%238%234%221%200%197%188%140$" var bytes = foo.split("%");  var b = new Buffer(bytes.length); for (var i = 0;i < bytes.length;i++) {         b[i] = bytes[i]; }  fs.writeFile("test.txt", b,  "binary",function(err) {     if(err) {         console.log(err);     } else {         console.log("The file was saved!");     } }); 

You can try to run it on your NodeJS and see that the result is wrong.

What can I do to fix it?

Answer 1

I am not sure if this would help but try to change the b variable to the bytes variable in the line below at least you would be able to view the file in a test editor

fs.writeFile("test.txt", b,  "binary",function(err) { }); 

If you would like to have the numbers space separated try the code below:

var fs = require('fs');  var foo = "71%73%70%56%57%97%50%0%50%0%247%0%0%150%140%115%102%94%69%198%187%159%123%114%90%71%71%71%138%129%101%202%193%166%201%193%172%238%234%221%200%197%188%140" var bytes = foo.split("%");  var b = new Buffer(bytes.length); var c = ""; for (var i = 0;i < bytes.length;i++) {     b[i] = bytes[i];     c = c + " " + bytes[i] }  fs.writeFile("test.txt", c,  "binary",function(err) {     if(err) {         console.log(err);     } else {         console.log("The file was saved!");     } }); 

Answer 2

You can try this:

var writeFileSync = function (path, buffer, permission) {     permission = permission || 438; // 0666     var fileDescriptor;      try {         fileDescriptor = fs.openSync(path, 'w', permission);     } catch (e) {         fs.chmodSync(path, permission);         fileDescriptor = fs.openSync(path, 'w', permission);     }      if (fileDescriptor) {         fs.writeSync(fileDescriptor, buffer, 0, buffer.length, 0);         fs.closeSync(fileDescriptor);     } }  // then writeFileSync('path_to_your_file', your_buffer);