How can I rewrite the following CURL command, so that it doesn't use the -F option, but still generates the exact same HTTP request? i.e. so that it passes the multipart/form-data in the body directly.
curl -X POST -F example=test http://localhost:3000/test
Solved:
curl \
-X POST \
-H "Content-Type: multipart/form-data; boundary=----------------------------4ebf00fbcf09" \
--data-binary @test.txt \
http://localhost:3000/test
Where test.txt contains the following text, and most importantly has CRLF (\r\n) line endings:
------------------------------4ebf00fbcf09
Content-Disposition: form-data; name="example"
test
------------------------------4ebf00fbcf09--
Notes: it is important to use --data-binary instead of plain old -d as the former preserves the line endings (which are very important). Also, note that the boundary in the body starts with an extra --.
I'm going to repeat it because it's so important, but that request-body file must have CRLF line endings. A multi-platform text editor with good line-ending support is jEdit (how to set the line endings in jEdit).
If you're interested in how I worked this out (debugging with a Ruby on Rails app) and not just the final solution, I wrote up my debugging steps on my blog.
You can use the --form argument with an explicitly
curl -H "Content-Type: multipart/related" \
--form "data=@example.jpg;type=image/jpeg" http://localhost:3000/test
Here's an alternative answer with the original CURL statement re-written using -d as a one-liner, without temporary files. Personally I think the temporary files approach is easier to understand, but I'm putting this here for reference as well:
curl -X POST -H "Content-Type: multipart/form-data; boundary=----------------------------4ebf00fbcf09" -d $'------------------------------4ebf00fbcf09\r\nContent-Disposition: form-data; name="example"\r\n\r\ntest\r\n------------------------------4ebf00fbcf09--\r\n' http://localhost:3000/test
Notes: the $'blar' syntax is so that bash will parse the \r\n as a CRLF token. Thanks to this answer for that tip.
This is what I'm using, I think it's clean and doesn't need temporary files nor gobbles up RAM in case you want to upload whole files (so no reading files into memory).
# Set these two.
file='path/to/yourfile.ext'
url='http://endpoint.example.com/foo/bar'
delim="-----MultipartDelimeter$$$RANDOM$RANDOM$RANDOM"
nl=$'\r\n'
mime="$(file -b --mime-type "$file")"
# This is the "body" of the request.
data() {
# Also make sure to set the fields you need.
printf %s "--$delim${nl}Content-Disposition: form-data; name=\"userfile\"${nl}Content-Type: $mime$nl$nl"
cat "$file"
printf %s "$nl--$delim--$nl"
}
# You can later grep this, or something.
response="$(data | curl -# "$url" -H "content-type: multipart/form-data; boundary=$delim" --data-binary @-)"
This is to upload one image file using "Content-Type: multipart/related",
curl --trace trace.txt -X POST -H 'Content-Type: multipart/related; boundary=boundary_1234' --data-binary $'--boundary_1234\r\nContent-Type: application/json; charset=UTF-8\r\n\r\n{\r\n\t"title": "TestFile"\r\n}\r\n\r\n--boundary_1234\r\nContent-Type: image/jpeg\r\n\r\n' --data-binary '@Image0177.jpg' --data-binary $'\r\n--boundary_1234--\r\n' 'http://localhost:3000/google/upload/drive/v2/files?uploadType=multipart'
Here it is how I would do it:
curl https://httpbin.org/post \
-H 'content-type: multipart/form-data; boundary=----FormBoundary123456789' \
--data-binary $'------FormBoundary123456789\r
Content-Disposition: form-data; name="example"\r
\r
test\r
------FormBoundary123456789--\r
'
Or a bit more sophisticated (should be portable to most modern shells):
DELIM=----FormBoundary$RANDOM$RANDOM
curl https://httpbin.org/post \
-H "content-type: multipart/form-data; boundary=$DELIM" \
--data-binary --$DELIM$'\r
Content-Disposition: form-data; name="example"\r
\r
test\r
'--$DELIM--$'\r
'
This is for multipart/form-data request method. for uploading a file add --form filename="@path/image.jpg;type=image/jpeg"
curl --form key="value" --form key="value" http://localhost:3000/test
