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FRCAPI Question on If-Modified-Since Header
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09/05/2016 4:42 PM
post4878
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FRCAPI Question on If-Modified-Since Header
I'm building a package in R (github.com/irwinsnet/firstapiR) for downloading and analyzing FIRST API server data. I am
currently adding conditional update functionality to the package that uses the "If-Modified-Since" header.
Question:
According to my testing, If I request data from the server using the "If-Modified-Since" header, and the value of the "
If-Modified-Since" header exactly matches the "Last-Modified" value, the server is returning the requested data (200
response) instead of a 304 response indicating the data has not been updated. Is this intentional?
It seems counter-intuitive. If I request data from the server, and store the value of the "Last-Modified" header as the
apiary documentation suggests, and then return that exact same value to the server in the "If-Modified-Since" header, it
seems I should
get a 304 response. Otherwise, if I want to reduce load on the server, my client would need to add a second to the "Last
-Modified" value before returning the value via the "If-Modified-Since" header -- which seems cumbersome. I can't help
but wonder if this is an error, especially since the apiary documentation doesn't say anything about having to add a
time interval to the "Last-Modified" value before returning it via "If-Modified-Since"
Details:
1. I requested data from the sever and recorded the value of the "Last-Modified" header.
Request URL: "https://frc-api.firstinspires.org/v2.0/2016/schedule/WAELL?tournamentLevel=qual"
Last Modified Header returned from server: "Fri, 18 Mar 2016 08:27:07 GMT"
2. I requested data again from the sever using the same URL, but I put the date-time returned in step 1 ("Fri, 18 Mar
2016 08:27:07 GMT") in the "If-Modified-Since" header. The server returned the entire schedule with status 200.
3. I added one second to the date-time and again called the same URL as in step 1, but with the revised date-time ("Fri,
18 Mar 2016 08:27:08 GMT") in the "If-Modified-Since" header. The server gave me a 304 response.
Thanks,
Stacy Irwin
FRC 1318
Issaquah Robotics Society
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