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I'm adding a feature for downloading files from web servers. I'm testing my program with my own Google Drive account, but I'm not sure how I should deal with the Content-Type Header because I don't know much about web programming.

Firstly, I uploaded two files to my google drive account. Both were the exactly same zip files but I renamed the extension of one of them from "zip" to "ktx" which means nothing before uploading just for the test. After uploading, I checked Content-Type headers of them and got "application/zip" for the original one and "application/x-zip" for the renamed one.

I was confused so searched for the Content-Type Header but just got more confused. Because it seems there are more names for a zip, such as "multipart/x-zip" and "application/x-zip-compressed". So I really want to know if there's a standard naming convention for the Content-Type header.

Anyways I uploaded all the file types I need and below is what I got from Google Drive.

Documents

text/plain (txt)

application/pdf

application/msword (doc)

application/vnd.ms-powerpoint (ppt)

application/vnd.ms-excel (xls)

application/rtf

application/vnd.openxmlformats-officedocument.wordprocessingml.document (docx)

application/vnd.openxmlformats-officedocument.presentationml.presentation (pptx)

application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (xlsx)

Images

image/jpeg

image/png

image/gif

image/tiff (tif, tiff)

image/x-ms-bmp

image/x-photoshop (psd)

image/x-raw (raw)

application/illustrator (ai)

Compressed

application/zip

application/rar

application/x-tar (tar)

application/x-gzip (gz)

application/x-7z-compressed (7z)

application/x-zip (When zip, jar, xlsx or apk is renamed to meaningless one.)

Audio files

audio/mpeg (mp3)

audio/x-wav

audio/x-ms-wma

audio/x-aiff (aiff)

audio/midi (mid)

application/ogg

Videos

video/mp4

video/x-msvideo (avi)

video/x-ms-asf

video/flv

video/quicktime (mov)

video/mpeg (mpg, vob)

video/x-ms-wmv

video/x-matroska (mkv)

Script or Source code files

text/html (htm, html)

text/x-csrc

text/x-c++src

text/x-csharp

text/x-java

text/x-python

text/css

application/x-javascript (js)

application/x-httpd-php

application/json

application/xml

Compiled or Executables

application/x-msdos-program (exe, dll, com, bat)

application/java-vm (class)

application/java-archive (jar)

application/x-python-code (pyc)

application/vnd.android.package-archive (apk)

Etc

application/x-shockwave-flash (swf)

  1. Is there any standard naming convention?

  2. Is it okay just to use the names above to check the MIME type?

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Jenix
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1 Answers1

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Is there any standard naming convention?

Is it okay just to use the names above to check the MIME type?

For the standard types, see Iana Media Types.

For MIME types, see Iana MIME Media Type Parameters.

[RFC2046] specifies that Media Types (formerly known as MIME types) and Media Subtypes will be assigned and listed by the IANA.

The file types are determined once when uploading or the server always checks when downloading?

Normally, when the file is requested, the server will check the file extension and determine the media type to use. Some servers however might check the first bytes of the file (magic number) to determine what the file type is (for example, zip-files start with PK.. - dots being 0x03 0x04).

This is likely the reason you are seeing "application/zip" for .zip and "application/x-zip" for zipped .ktx. As a side note: .xlsx is a zipped file too.

Depending on the implementation, the server might check this once when receiving the file, and store it for later use, or check it with each download.

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Danny_ds
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  • Thanks a million! :) – Jenix Jan 08 '16 at 17:52
  • Could I ask one more question? The file types are determined once when uploading or the server always checks when downloading? – Jenix Jan 08 '16 at 17:58
  • Wow!! Thank you thank you thank you!! It helped a lot!! – Jenix Jan 08 '16 at 18:39
  • And exactly!! I tested and .xslx is x-zip just as you said. – Jenix Jan 08 '16 at 18:44
  • @Jenix - Was that after changing the .xlsx extension, or _with_ .xlsx extension? (that would be strange - see http://stackoverflow.com/questions/4212861/what-is-a-correct-mime-type-for-docx-pptx-etc ) – Danny_ds Jan 08 '16 at 18:51
  • As I wrote above in my question, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" for ".xlsx", because Google Drive reads a .xlsx file with its own viewer. I tried again with a renamed file -renamed before uploading- and checked it, "application/x-zip" this time. – Jenix Jan 08 '16 at 19:01
  • But renaming the extension after uploading doesn't work this way. – Jenix Jan 08 '16 at 19:05