Hello,

I am trying to query table.json via the API. Using Postman or curl my results look great.

https://x.y.z/api/table.json?content=devices&columns=device,host,tags&output=json&filter_tags=@tag(IOS,NXOS,DNOS,FTOS,FortiOS,EtherHaul,SonicOS,AirFiber)&filter_type=@sub(device)&sortby=name&username=YYYY&passhash=xxxxxxxx&filter_status=3&filter_status=4

Do API responses send data back using zlib/deflate?

The application I am trying to integrate with (Oxidizer) keeps thinking the PRTG response is zlib compressed; however, fails to decompress the data correctly.

Thank you kindly

Article Comments

Hi tlister,

If you use the JSON output, the content is encoded by "deflate". You can also check this via the developer tools of your browser (network tab)-


Jan, 2020 - Permalink

Hello Moritz,

Thank you for the reply.

Yes, when I query the API with the "deflate" header set in my query, the returned data does not appear to be encoded correctly (I am unable to uncompress the data as I would expect).

Below is an example to illustrate what I'm trying to communicate.

curl -H "Accept-Encoding: gzip, deflate, identity" "https://xyz/api/table.json?content=devices&columns=device,host,tags&output=json&filter_tags=@tag(IOS,NXOS,DNOS,FTOS,FortiOS,EtherHaul,SonicOS,AirFiber)&filter_type=@sub(device)&sortby=name&username=oxidizer&passhash=xxxxxxxx&filter_status=3&filter_status=4" -k > test
$ zlib-flate -uncompress < test
flate: inflate: data: incorrect header check

If I do the same query without specifying 'deflate" the results are returned uncompressed and as expected.

The author of the other application I am integrating against has suggested that I contact Paessler to verify there are no known bugs with how the returned data is compressed using 'deflate'.

In addition, for my own sanity in getting this working, is there a flag I can set in a PRTG config file to disable support for 'deflate compression' similar as to how I would in other web servers such as nginx/apache/etc?

Kind regards,


Jan, 2020 - Permalink

Hi tlister,

Thank you for the update.

I talked with a colleague and he mentioned that "deflate" is only used when the other side accepts "deflate".


Jan, 2020 - Permalink

Hi Moritz,

Either forum is fine; however, in the interest of someone else having a similar issue as me, I'd like this info to remain public.

Regarding the returned compressed 'deflate' data. The reason I'm opening this ticket is because I believe the data being returned by the PRTG API is not compressed correctly when I set "deflate" on my query.

When I try to uncompress the results of my query (with multiple tools, one example is in my previous message) I am given the same error of "incorrect header check". I and others I have been working with believe PRTG may not be compressing the data correctly.

I would just like to confirm that there are no known issues with the PRTG API when using gzip compression (deflate).

Thanks,


Jan, 2020 - Permalink

Hi tlister,

Thank you for the information.

I talked with the developer and received the information that the "deflate" version is not the latest one. Therefore, it's possible that "deflate" is not correctly recognized.


Jan, 2020 - Permalink