Handling HTTP Requests¶
Add or Modify an HTTP Header¶
You may want to add some extra HTTP header to the response.
In this example we’ll be adding the header X-Content-Type-Options
to the response.
1 2 3 4 5 6 7 8 9 10 | $ cat sniff-route #!/usr/bin/env sh kapow route add /sec-hello-world - <<-'EOF' kapow set /response/headers/X-Content-Type-Options nosniff kapow set /response/headers/Content-Type text/plain echo this will be interpreted as plain text | kapow set /response/body EOF $ kapow server nosniff-route |
Testing with curl:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | $ curl -v http://localhost:8080/sec-hello-world * Trying ::1... * TCP_NODELAY set * Connected to localhost (::1) port 8080 (#0) > GET /sec-hello-word HTTP/1.1 > Host: localhost:8080 > User-Agent: curl/7.54.0 > Accept: */* > < HTTP/1.1 200 OK < X-Content-Type-Options: nosniff < Date: Wed, 20 Nov 2019 10:56:46 GMT < Content-Length: 24 < Content-Type: text/plain < this will be interpreted as plain text |
Warning
Please be aware that if you don’t explicitly specify the value of
the Content-Type
header, Kapow! will guess it, effectively
negating the effect of the X-Content-Type-Options
header.
Note
You can read more about the X-Content-Type-Options: nosniff
header here.
Upload Files¶
Example #1¶
Uploading a file using Kapow! is very simple:
1 2 3 4 5 | $ cat upload-route #!/usr/bin/env sh kapow route add -X POST /upload-file - <<-'EOF' kapow get /request/files/data/content | kapow set /response/body EOF |
1 2 3 4 | $ cat results.json {"hello": "world"} $ curl -X POST -H 'Content-Type: multipart/form-data' -F data=@results.json http://localhost:8080/upload-file {"hello": "world"} |
Example #2¶
In this example we reply the line count of the file received in the request:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | $ cat count-file-lines #!/usr/bin/env sh kapow route add -X POST /count-file-lines - <<-'EOF' # Get sent file FNAME=$(kapow get /request/files/myfile/filename) # Counting file lines LCOUNT=$(kapow get /request/files/myfile/content | wc -l) kapow set /response/status 200 echo "$FNAME has $LCOUNT lines" | kapow set /response/body EOF |
1 2 3 4 5 | $ cat file.txt hello World $ curl -F myfile=@file.txt http://localhost:8080/count-file-lines file.txt has 2 lines |
Sending HTTP error codes¶
You can specify custom status code for HTTP
response:
1 2 3 4 5 6 | $ cat error-route #!/usr/bin/env sh kapow route add /error - <<-'EOF' kapow set /response/status 401 echo -n '401 error' | kapow set /response/body EOF |
Testing with curl:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | $ curl -v http://localhost:8080/error * Trying ::1... * TCP_NODELAY set * Connected to localhost (::1) port 8080 (#0) > GET /error HTTP/1.1 > Host: localhost:8080 > User-Agent: curl/7.54.0 > Accept: */* > < HTTP/1.1 401 Unauthorized < Date: Wed, 20 Nov 2019 14:06:44 GMT < Content-Length: 10 < Content-Type: text/plain; charset=utf-8 < 401 error |
How to redirect using HTTP¶
In this example we’ll redirect our users to Google
:
1 2 3 4 5 6 | $ cat redirect #!/usr/bin/env sh kapow route add /redirect - <<-'EOF' kapow set /response/headers/Location https://google.com kapow set /response/status 301 EOF |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | $ curl -v http://localhost:8080/redirect * Trying ::1... * TCP_NODELAY set * Connected to localhost (::1) port 8080 (#0) > GET /redirect HTTP/1.1 > Host: localhost:8080 > User-Agent: curl/7.54.0 > Accept: */* > < HTTP/1.1 301 Moved Permanently < Location: http://google.com < Date: Wed, 20 Nov 2019 11:39:24 GMT < Content-Length: 0 < * Connection #0 to host localhost left intact |
Manage Cookies¶
If you track down some user state, Kapow! allows you manage Request/Response Cookies.
In the next example we’ll set a cookie:
1 2 3 4 5 6 7 8 9 10 11 | $ cat cookie #!/usr/bin/env sh kapow route add /setcookie - <<-'EOF' CURRENT_STATUS=$(kapow get /request/cookies/kapow-status) if [ -z "$CURRENT_STATUS" ]; then kapow set /response/cookies/Kapow-Status 'Kapow Cookie Set' fi echo -n OK | kapow set /response/body EOF |
Calling with curl:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | $ curl -v http://localhost:8080/setcookie * Trying ::1... * TCP_NODELAY set * Connected to localhost (::1) port 8080 (#0) > GET /setcookie HTTP/1.1 > Host: localhost:8080 > User-Agent: curl/7.54.0 > Accept: */* > < HTTP/1.1 200 OK < Set-Cookie: Kapow-Status="Kapow Cookie Set" < Date: Fri, 22 Nov 2019 10:44:42 GMT < Content-Length: 3 < Content-Type: text/plain; charset=utf-8 < OK * Connection #0 to host localhost left intact |