Adobe’s done a real whiz-bang job with their scripting support, known as ExtendScript. They’ve filled in some important missing pieces to make JavaScript into a full-featured programming environment, include network communications, XML, and graphic UI elements. These are uniformly available across all their scriptable applications (with, alas, minor variations with the UI support).
This post shows a little example of how to use the humble File object.
Like all good library writers, they’ve designed File to shield us from the absolute blazing stupidity of different linefeed characters. It detects CR, LF, LFCR, and CRLF and still chugs along reading your files, line by line, correctly. No, really, it does work!
So the exciting case of course is, how to defeat that and read or write binary files? This example demonstrates the recipe.
// adobe extendscript writing binary data
var f = new File("/Users/poly/junk/jsbinTest.bin");
f.encoding = "BINARY";
f.open ("w");
for(i = 0; i < 256; i++)
f.write(String.fromCharCode (i));
f.write("this file is: " + f.fsName + "\n");
f.close();
They've got this highly-developed notion of "encoding", but, in truth, you can usually either ignore it, for text, or set it to the magic value BINARY. Easy peasy!
Note also the standard JavaScript String.fromCharCode(integer).
And here's the file created by that ExtendScript code snippet.
poly@Omino-Lux: hexdump -C ~/junk/jsbinTest.bin
00000000 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f |................|
00000010 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f |................|
00000020 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f | !"#$%&'()*+,-./|
00000030 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f |0123456789:;<=>?|
00000040 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f |@ABCDEFGHIJKLMNO|
00000050 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f |PQRSTUVWXYZ[\]^_|
00000060 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f |`abcdefghijklmno|
00000070 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f |pqrstuvwxyz{|}~.|
00000080 80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f |................|
00000090 90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f |................|
000000a0 a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af |................|
000000b0 b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf |................|
000000c0 c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf |................|
000000d0 d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df |................|
000000e0 e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef |................|
000000f0 f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd fe ff |................|
00000100 74 68 69 73 20 66 69 6c 65 20 69 73 3a 20 2f 55 |this file is: /U|
00000110 73 65 72 73 2f 70 6f 6c 79 2f 6a 75 6e 6b 2f 6a |sers/poly/junk/j|
00000120 73 62 69 6e 54 65 73 74 2e 62 69 6e 0a |sbinTest.bin.|
So why interact with binary files and, oh, say, After Effects? I have some ideas...