Title: | Welcome to WEB_AUTHORING |
Notice: | Before writing, please check for an existing topic |
Moderator: | VAXCAT::LAURIE |
Created: | Tue Mar 05 1996 |
Last Modified: | Thu Jun 05 1997 |
Last Successful Update: | Fri Jun 06 1997 |
Number of topics: | 186 |
Total number of notes: | 1479 |
Can someone explain to me the various incantations for MIME types? I wanted to place a BMP on my webpage, and have it displayed, in much the same way GIFs and JPGs are. As I researched this, it seemed as if it might not be possible, until I found a page that did it! My head is spinning! I'll leave off the long story, and get down to my research: Using an out-of-the-box Netscape FastTrack server, I created a page with two variations on it: <img src="bermuda8.bmp"> <a href="bermuda8.bmp">bermuda</a> The image comes up "broken". If I click on the word "bermuda", it displays gobbledy-goop in the text viewer window. Same if I right click on the broken image and choose "View image (bermuda8.bmp). Under View->document info, it tells me that image bermuda8.bmp is type text/plain. I assumed that the incorrect MIME type was causing the problem. First I checked out my browser (Netscape Gold 3.0). Turns out that it actually has a defined MIME type for .BMP files of image/x-MS-bmp. Hmmm, sounds right. I configured my browser to handle x-MS-bmp with LVIEW. However, since the wrong MIME type was being sent, it never caught it. So I edited the mime.types file to include x-MS-bmp for .BMP extensions. The image still comes up broken, BUT if I click on either the word Bermuda, or right click on the image and choose view, it will now launch the LVIEW app to display the image (if I *don't* configure the browser to use LVIEW, then I get the dialog for unknown MIME types, which is sort've ok). At this point I'm thinking I'll just have to have both a JPG *and* a BMP, let the user "see" the JPG, and if they click on it, then I'll download the BMP (the whole point is to allow the user to download BMP wallpaper for Windows). But then I tried some research. I did an Altavista search on image:*.bmp, and it came up with a bunch of hits. Moreover when I visited one of these pages, even with a default browser, BMP files are displayed as images IN PLACE! But when I went to VIEW INFO, it tells me the image is TEXT/PLAIN!!!! So, I click on the image to view it, and instead of an image, it runs the text viewer, and shows me this: #define aso3_width 16 #define aso3_height 16 static unsigned char aso3_bits[] = { 0x00, 0x00, 0xe0, 0x07, 0xb0, 0x0a, 0xf8, 0x1f, 0xfc, 0x1f, 0x56, 0x35, 0xea, 0x2f, 0x36, 0x54, 0x2c, 0x6c, 0xb4, 0xd5, 0xec, 0xae, 0x74, 0xd5, 0xac, 0xbf, 0xf4, 0x61, 0x34, 0xc0, 0x1c, 0x80}; The image tag is a typical <img src="xyz.bmp">. It doesn't have a special MIME type. Yet, Netscape knows how to deal with this thing. How???? And what is it? It obviously won't suit my needs, because I want to put Windows wallpaper on the page for downloading, and this obviously isn't windows wallpaper. But what causes it to be recognized as an image? Also, is creating an HREF tag the best I can do (possibly with a JPG image in it)? No one wants broken pictures on their page. jeb (P.S. The URL, FYI, is: http://www.mit.edu:8001/activities/arab/homepage.html )
T.R | Title | User | Personal Name | Date | Lines |
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172.1 | HOUBA::MEHERS | Damian, http://bigbird.geo.dec.com/ | Wed Apr 09 1997 10:39 | 4 | |
A guess - try flushing all cash in Browser. /Damian | |||||
172.2 | Do you need to bother? | HNDYMN::MCCARTHY | A Quinn Martin Production | Wed Apr 09 1997 11:59 | 8 |
>> download the BMP (the whole point is to allow the user to download BMP >> wallpaper for Windows). Um, Netscape 3.0 has a "set as wallpaper" function that I've used to set the background of .jpg files. You mb2 (or right-most mb button) while over the gif/jpg image and the popup has a "set as wallpaper" option. bjm | |||||
172.3 | it is just a text file | HNDYMN::MCCARTHY | A Quinn Martin Production | Wed Apr 09 1997 12:46 | 40 |
Another note: >> The image tag is a typical <img src="xyz.bmp">. It doesn't have a >> special MIME type. Yet, Netscape knows how to deal with this thing. Um, I don't think you'll find MIME incoding inside of GIF or JPG files either, they are just not as nice to look at as BMP (gee that looks like X bitmap files). Utilities like xv, Imagemagick just look for a "magic number" of sorts inside the file. For bmp or xmp files, that "magic number" is several lines. The <img src= has told Netscape to try to treat this as an image so it started looking for the "magic". I just did a quick test and Netscape (OpenVMS version) displays the "quote_icon.bmp" correctly when it is included as: <img src="quote_icon.bmp">Quote Icon That file is below. Brian J. #define decw_quote_sm_width 32 #define decw_quote_sm_height 32 static char decw_quote_sm_bits[] = { 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55, 0xfa, 0xab, 0xaa, 0xaa, 0x01, 0x57, 0x55, 0x55, 0x52, 0xaa, 0xaa, 0xaa, 0x51, 0x56, 0x55, 0x55, 0x52, 0xaa, 0xaa, 0xaa, 0x51, 0x56, 0x55, 0x55, 0x52, 0xaa, 0xaa, 0xaa, 0x11, 0x56, 0x55, 0x55, 0xf2, 0xaa, 0xaa, 0xaa, 0x01, 0x55, 0x55, 0x55, 0xaa, 0xfa, 0xaf, 0xaa, 0x55, 0x01, 0x54, 0x55, 0xaa, 0xa2, 0xac, 0xaa, 0x55, 0x65, 0x54, 0x55, 0xaa, 0xe2, 0xaa, 0xaa, 0x55, 0x05, 0x55, 0x55, 0xaa, 0xa2, 0xab, 0xaa, 0x55, 0x65, 0x56, 0x55, 0xaa, 0xe2, 0xec, 0xaf, 0x55, 0x01, 0x14, 0x54, 0xaa, 0xaa, 0x8a, 0xa8, 0x55, 0x55, 0x45, 0x51, 0xaa, 0xaa, 0xca, 0xaa, 0x55, 0x55, 0x45, 0x5d, 0xaa, 0xaa, 0xca, 0xaa, 0x55, 0x55, 0xc5, 0x53, 0xaa, 0xaa, 0x8a, 0xa8, 0x55, 0x55, 0x15, 0x54, 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55}; | |||||
172.4 | 8153::tecotoo.mro.dec.com::mayer | Danny Mayer | Wed Apr 09 1997 14:28 | 5 | |
I think that you are looking at the wrong end. The MIME type of any file is sent by the server in the HTTP header. Check to see what your Fasttrack server has set BMP to send as a MIME type. Danny | |||||
172.5 | PCBUOA::BAYJ | Jim, Portables | Wed Apr 09 1997 18:14 | 30 | |
>I think that you are looking at the wrong end. The MIME type of any >file is sent by the server in the HTTP header. Check to see what your >Fasttrack server has set BMP to send as a MIME type. Thats my point. The server doesn't *have* a .BMP type defined. FastTrack uses a file called "mime.types" to define the known variations. There is no occurance of "bmp" in the file. Moreover, when I use View->Doc-info, it says the MIME typ being sent for the .BMP file is text/plain, (on both the FastTrack server, and on the remote server where I found the "correctly" displayed BMP files). Its clear that the browser magically figures out what to do with the BMP file, even though there is no obvious association in the mime.types file for BMP files, and the remote server is obviously not sending any specific MIME type that the browser might use to figure it out. So, what mechanism enables the BMP file (the one stored as text format) to be displayed properly? And what is the technical name of that format? I just went back to the page with the .BMP file, saved it in my windows directory, and tried to set my wallpaper to it. As expected, that format is not accepted. And, since Netscape easily converts JPGs and GIFs (and, as it turns out, the text format BMP files - worked like a champ) to BMP files for the purposes of creating wallpaper, how come they didn't bother to allow it to go the other way? How come native Netscape can't display a BMP file? Aren't BMP files pretty common? jeb | |||||
172.6 | QUARK::LIONEL | Free advice is worth every cent | Wed Apr 09 1997 18:50 | 4 | |
No, the browser doesn't "magically figure it out". If the server is sending text/plain, that's what the browser will try to view it as. Steve | |||||
172.7 | 8153::tecotoo.mro.dec.com::mayer | Danny Mayer | Wed Apr 09 1997 19:14 | 17 | |
> Thats my point. The server doesn't *have* a .BMP type defined. > FastTrack uses a file called "mime.types" to define the known > variations. There is no occurance of "bmp" in the file. Moreover, > when I use View->Doc-info, it says the MIME typ being sent for the .BMP > file is text/plain, (on both the FastTrack server, and on the remote > server where I found the "correctly" displayed BMP files). If the server can't determine the MIME type to send then it will use the default MIME type, which in the case of YOUR server is apparently text/plain. The default MIME type is settable. It is not clear from your message what platform the server is running on. However if this is a Windows NT system then the chances are that the MIME types are stored in the registry rather than in a file. In that case check the Registry for MIME types. I just checked with Greg: on NT it uses the Registry for the MIME types. Danny | |||||
172.8 | PCBUOA::BAYJ | Jim, Portables | Wed Apr 09 1997 20:15 | 60 | |
Okay, two separate issues. Re: registry, the FastTrack Server 2.0 on NT may very well use the registry at runtime, but when the server starts, it loads the MIME types from the file mime.types, which is located in netscape\server\httpd-SERVERNAME\config. There may be some "default" MIME types in teh registry that don't occur in the mime.types file, though that seems unlikely. But when I make changes to the file mime.types, and restart the server, the new types are available. Second issue: I just tried it. I copied over the text format BMP file from the web page I found it on, and put it on my test page. I pulled it up, and sure enough, it was displayed in place on the page, right below the "broken" picture which points to my Windows BMP file. I used VIEW->DOC INFO, which said the MIME type it received is x-MS-bmp. Thats a red herring, because *I* put that type in the mime.types file of the FastTrack server. So, I stopped the server, commented out that type, and restarted. Here's the image section of the mime.types file: type=image/gif exts=gif type=image/ief exts=ief type=image/jpeg exts=jpeg,jpg,jpe type=image/tiff exts=tiff,tif type=image/x-cmu-raster exts=ras type=image/x-portable-anymap exts=pnm type=image/x-portable-bitmap exts=pbm type=image/x-portable-graymap exts=pgm type=image/x-portable-pixmap exts=ppm type=image/x-rgb exts=rgb type=image/x-xbitmap exts=xbm type=image/x-xpixmap exts=xpm type=image/x-xwindowdump exts=xwd #type=image/x-MS-bmp exts=bmp ^ comment symbol Now, when I do the same test, without any BMP MIME type known to the server, the text format BMP file (can anyone tell me what that format is called?) again displays just fine, and my Windows BMP is still "broken". VIEW->DOC INFO now says the MIME type of the text BMP is text/plain. In fact, while in the VIEW->DOC INFO window, if I click on the link for the text BMP, when it comes up, its not the actual image, but rather the text. So, completely independent of any "obvious" MIME information being sent from the server, the browser still somehow knows that the text BMP file is actually an image. So, in light of this, I guess the question is, why does Netscape interpret the content of a text BMP file as an image, without any MIME cues? I've never heard of Netscape understanding about this odd text format bitmap (the other question is why DON'T they internally handle processing of Windows format BMP files, but thats really a political question). jeb | |||||
172.9 | BIGUN::nessus.cao.dec.com::Mayne | A wretched hive of scum and villainy | Thu Apr 10 1997 00:42 | 7 | |
The bitmap files in .0 and .3 are XBM (X bitmap) format files. Presumably the server is sending them as text/plain, and the client is clever enough to realise that they're XBM format. ? PJDM | |||||
172.10 | still think Netscape is peaking at the data stream | HNDYMN::MCCARTHY | A Quinn Martin Production | Thu Apr 10 1997 03:01 | 13 |
>>The bitmap files in .0 and .3 are XBM (X bitmap) format files. Presumably the Correct. >>server is sending them I accessed my sample page using file:/ so there was no server in the way. That was part of the reason I assumed netscape was doing some processing on what it got for in-lined images (it has to display them). Netscape has the ability to display many image formats in-line (ie no help of an external program). bjm | |||||
172.11 | Just add it to mime.types! | ANGLER::GRENIER | Thu Apr 10 1997 04:47 | 14 | |
Just add an entry to your mime.types file for BMP files. Fastrack Server on Digital Unix defaults to text/plain for file types that it doesn't find in mime.types. I imagine the NT version is the same. Add something like: type=image/bmp exts=bmp ...and restart your server. I've had to do this many times, so that my webserver would not send Word/Powerpoint/etc files as plain text. If you start adding other types of content that Fastrack doesn't know about, you'll have to add those mime types also. I recently added mime types for Shockwave Director and Futuresplash. Steve | |||||
172.12 | 8153::tecotoo.mro.dec.com::mayer | Danny Mayer | Thu Apr 10 1997 15:14 | 12 | |
> I accessed my sample page using file:/ so there was no server in the way. > That was part of the reason I assumed netscape was doing some > processing on what it got for in-lined images (it has to display them). > Netscape has the ability to display many image formats in-line (ie no help > of an external program). Files read using file: protocol use the browser's list of MIME types since there is no HTTP header. This is the same for ftp: protocol. The results you get are different from using http: protocol since the http server decides on the MIME type to send in the HTTP header. Danny | |||||
172.13 | BMP file format | CIRCUS::GOETZE | Tibetan karma not Made in China | Wed May 14 1997 00:19 | 4 |
BMP is common on Windows, but makes for a poor network graphics file format. The files are typically huge, and the format O/S-specific. erik |