Download PNG Via TcpClient
Hey all I am having a problem downloading a PNG image file using TcpClient. My program connects to a proxy, request a web page and decides to download the Image. It sends the request and I get the Response:
PacketLog:
Code:
0000 48 54 54 50 2F 31 2E 31 20 32 30 30 20 4F 4B 0D HTTP/1.1 200 OK.
0010 0A 44 61 74 65 3A 20 54 68 75 2C 20 32 35 20 44 .Date: Thu, 25 D
0020 65 63 20 32 30 30 38 20 30 35 3A 32 34 3A 35 37 ec 2008 05:24:57
0030 20 47 4D 54 0D 0A 53 65 72 76 65 72 3A 20 41 70 GMT..Server: Ap
0040 61 63 68 65 2F 31 2E 33 2E 32 37 20 28 55 6E 69 ache/1.3.27 (Uni
0050 78 29 20 6D 6F 64 5F 70 65 72 6C 2F 31 2E 32 37 x) mod_perl/1.27
0060 20 50 48 50 2F 34 2E 34 2E 36 0D 0A 50 72 61 67 PHP/4.4.6..Prag
0070 6D 61 3A 20 6E 6F 2D 63 61 63 68 65 43 61 63 68 ma: no-cacheCach
0080 65 2D 63 6F 6E 74 72 6F 6C 3A 20 6E 6F 2D 63 61 e-control: no-ca
0090 63 68 65 0D 0A 53 65 74 2D 43 6F 6F 6B 69 65 3A che..Set-Cookie:
00A0 20 4D 46 49 6D 61 67 65 3D 53 59 47 6B 68 4A 44 MFImage=SYGkhJD
00B0 51 58 63 3B 20 65 78 70 69 72 65 73 3D 46 72 69 QXc; expires=Fri
00C0 2C 20 32 35 2D 44 65 63 2D 32 30 30 39 20 30 35 , 25-Dec-2009 05
00D0 3A 32 34 3A 35 37 20 47 4D 54 3B 20 70 61 74 68 :24:57 GMT; path
00E0 3D 2F 3B 0D 0A 50 72 61 67 6D 61 3A 20 6E 6F 2D =/;..Pragma: no-
00F0 63 61 63 68 65 0D 0A 43 61 63 68 65 2D 63 6F 6E cache..Cache-con
0100 74 72 6F 6C 3A 20 6E 6F 2D 63 61 63 68 65 0D 0A trol: no-cache..
0110 4C 61 73 74 2D 4D 6F 64 69 66 69 65 64 3A 20 46 Last-Modified: F
0120 72 69 2C 20 31 32 20 41 75 67 20 32 30 30 35 20 ri, 12 Aug 2005
0130 32 33 3A 34 39 3A 31 33 20 47 4D 54 0D 0A 43 6F 23:49:13 GMT..Co
0140 6E 6E 65 63 74 69 6F 6E 3A 20 63 6C 6F 73 65 0D nnection: close.
0150 0A 43 6F 6E 74 65 6E 74 2D 54 79 70 65 3A 20 69 .Content-Type: i
0160 6D 61 67 65 2F 70 6E 67 0D 0A 45 78 70 69 72 65 mage/png..Expire
0170 73 3A 20 54 68 75 2C 20 32 35 20 44 65 63 20 32 s: Thu, 25 Dec 2
0180 30 30 38 20 30 35 3A 32 34 3A 35 37 20 47 4D 54 008 05:24:57 GMT
0190 0D 0A 0D 0A 89 50 4E 47 0D 0A 1A 0A 00 00 00 0D .....PNG........
01A0 49 48 44 52 00 00 00 5A 00 00 00 14 04 03 00 00 IHDR...Z........
01B0 00 FF D4 37 2D 00 00 00 30 50 4C 54 45 04 02 04 ...7-...0PLTE...
01C0 24 22 24 74 76 74 44 46 44 8C 8A 8C BC BA BC 54 $"$tvtDFD......T
01D0 56 54 9C 9A 9C 64 66 64 34 32 34 14 12 14 FC FE VT...dfd424.....
01E0 FC EC EE EC CC CE CC AC AA AC DC DE DC 7E 9E 46 .............~.F
01F0 91 00 00 01 74 49 44 41 54 78 9C B5 92 BD 4B 03 ....tIDATx....K.
0200 41 10 C5 5F A2 89 7A 41 02 B6 69 FC E8 BC 32 92 A.._..zA..i...2.
0210 E6 10 D2 DB 88 90 C6 43 B4 4F 61 1A 41 48 13 B0 .......C.Oa.AH..
0220 B4 11 B4 4B 8A 03 B1 0A 42 CC 87 31 CE 9D 09 82 ...K....B..1....
0230 85 49 63 AD 7F C2 81 D8 A7 F1 ED 1D D1 70 9B C6 .Ic..........p..
0240 C2 57 CC EC 6F 66 77 66 76 59 E0 6F 5A 59 A7 56 .W..ofwfvY.oZY.V
0250 B9 D8 2A AC 29 4E 9E 9C 06 F1 AB C2 E6 0C B4 84 ..*.)N..........
0260 6A 00 0B 74 15 C0 B0 45 F6 19 5E 14 71 2F 34 0C j..t...E..^.q/4.
0270 77 0F 80 A2 1C C8 50 1D 7A 91 27 86 33 72 28 5F w.....P.z.'.3r(_
0280 1A E2 3A 9B DD 56 45 FD 7B 98 0F 0C BB 4E 55 58 ..:..VE.{....NUX
0290 A5 DC 84 AF A3 52 B1 4D 63 37 60 35 01 B3 CD 7A .....R.Mc7`5...z
02A0 79 60 FC 88 62 57 43 CA 18 A9 1E 66 0B 66 8F AE y`..bWC....f.f..
02B0 89 B8 EC 02 EC 9B E9 68 48 CD CB 11 ED 2D E7 2E .......hH....-..
02C0 05 C5 E2 BC C6 1C B7 A4 44 43 75 03 4F D9 D8 48 ........DCu.O..H
02D0 3C 07 A8 F6 9D 34 9F 68 92 8E A0 9A 21 18 BF C6 <....4.h....!...
02E0 DA EF 40 42 F6 EC A9 74 04 A9 F1 20 B0 2D EC F0 [email protected]... .-..
02F0 1E C6 87 78 53 E9 08 82 AB 92 1A 44 DE 50 77 B9 ...xS......D.Pw.
0300 88 7F 9E 31 B5 A4 D2 7D 1D 79 C9 4A 70 E6 A7 57 ...1...}.y.Jp..W
0310 5C 1D 67 41 AB 33 03 13 E2 04 B5 87 B0 78 FA A6 \.gA.3.......x..
0320 C0 00 DF C8 EE A9 D7 8B 22 90 72 83 12 B6 97 1B ........".r.....
0330 93 D3 B2 51 56 2D CF BD DC E8 4E 43 A0 1E 36 AC ...QV-....NC..6.
0340 F1 BB F0 4D 92 74 AF C4 65 FA BC 86 98 8C 17 F3 ...M.t..e.......
0350 A5 AB 46 3A 96 8E FA 6C 86 2F CF D0 F1 57 D9 D0 ..F:...l./...W..
0360 5D 3A E1 7F 98 8D FF A6 6F 32 59 DC 82 11 A2 B0 ]:......o2Y.....
0370 A5 00 00 00 00 49 45 4E 44 AE 42 60 82 .....IEND.B`.
Ok so, I use \r\n\r\n as the delimiter to remove the Header, then output the rest of the source into a PNG file but it is not working. Here is my Code:
Code:
int startPos = Response.IndexOf("\r\n\r\n");
byte[] theImage = Encoding.ASCII.GetBytes(Response.Substring( startPos + 4));
FileStream fStream = new FileStream("asdf.png",FileMode.Create);
fStream.Write(theImage,0,theImage.Length);
fStream.Flush(); fStream.Close();
Any ideas guys? This thing is becoming a pain :D
Re: Download PNG Via TcpClient
I think that ASCII encoding is limited to 7-bit values i.e. values of 0 through 127, or 0x0 to 0x7f in hex if you prefer.
Try using Encoding.UTF8, which is for use with 8-bit values and see if it works.
Re: Download PNG Via TcpClient
Quote:
Originally Posted by Andy_P
I think that ASCII encoding is limited to 7-bit values i.e. values of 0 through 127, or 0x0 to 0x7f in hex if you prefer.
Try using Encoding.UTF8, which is for use with 8-bit values and see if it works.
I tried Encoding.UTF8.GetBytes instead of Encoding.ASCII.GetBytes and still doesn't work. you have anymore ideas? I appreciate the help so far thank you
Re: Download PNG Via TcpClient
Does the file you create actually correspond to the data you expect it to?
In other words, does the first byte of the file have a value of 0x89?
Something else to try: Save all of the Response to a file, strip out the header manually with a hex editor of some sort, and see if the resultant file creates a valid .png image file.
Re: Download PNG Via TcpClient
What you're currently doing is taking the entire string containing the actual byte values of the picture and throwing it into a function that will return a byte array containing all the corresponding ASCII/UTF8 values for each character. Thats not really what you want, since the byte values you need are already there right infront of you in the response body ;)
