Web interface, JSON

Community Support
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1

https://learninghub.kx.com/forums/topic/web-interface-json

Hi - does anyone have a customization to the .z.ph handler that would allow the caller to receive JSON data, the same way that adding q.csv to the URL would result in a CSV file being returned from the server? TIA

2

enlist did the trick, thanks. The following works fine, no need for double .j.j / .j.k

f1:{enlist (`t1`t2)!(([]c1:`a`b`c;c2:1 2 3);([]c1:`d`e`f;c2:4 5 6))}
wget http://localhost:5000/test.json?f1` -O test.json

q).j.k raze read0`:test.json
t1| +`c1`c2!((,"a";,"b";,"c");1 2 3f)
t2| +`c1`c2!((,"d";,"e";,"f");4 5 6f)

 

3

Try enlisting

 

 

 

4

A quick solution could be utilise something like wget to download the json data instead.

Server

$ q -p 5000 -q 
q)show data:([]a:1+til 10;b:10?`4) 
a b 
------- 
1 milg 
2 igfb 
3 kaod 
4 bafc 
5 kfho 
6 jecp 
7 kfmo 
8 lkkl 
9 kfif 
10 fglg q
)`:html/test.json 0: enlist .j.j data

Client

$ wget http://localhost:5000/test.json 
--2023-09-12 10:46:40-- 
http://localhost:5000/test.json Resolving localhost (localhost)... 
127.0.0.1 Connecting to localhost (localhost)|127.0.0.1|:5000... connected. 
HTTP request sent, awaiting response... 200 OK 
Length: 193 [application/json] 
Saving to: test.json test.json 100%[====================================================>] 193 --.-KB/s in 0s 2023-09-12 10:46:40 (61.1 MB/s)- test.json saved [193/193] 
$ q -q 
q)first .j.k each read0 `:test.json 
a b 
--------- 
1 "milg" 
2 "igfb" 
3 "kaod" 
4 "bafc" 
5 "kfho" 
6 "jecp" 
7 "kfmo" 
8 "lkkl" 
9 "kfif" 
10 "fglg"

 

5

Thanks, but that doesn’t quite work for my needs. Instead of being able to say http://localhost:5000/.json?callfunc and get a JSON, the caller now has to make two requests, one to run the code and save the output on the filesystem, and then another to read the file from html/. And hope there were no requests in between, which can never be guaranteed.

6

You can do this in one call without saving the table to the filesystem from the client machine, and without needing to tweak the .z.ph (or .h.val) handlers

 

Note, if you run the same URL via the brower you’ll see the JSON there, it won’t automatically download like CSV files though.

 

Hope this helps, in lieu of more community suggestions

7

Thanks, that’s good to know. However, it only appears to work with plain tables, not other structures, e.g. dictionary of tables.

f1:{([]c1:`a`b`c;c2:1 2 3)} / works, but you can do the same with CSV

f1:{ (`t1`t2)! (([]c1:`a`b`c;c2:1 2 3);([]c1:`d`e`f;c2:4 5 6)) } / breaks, even though the structure is serializable through JSON
wget http://localhost:5000/test.json?f1[] -O test.json
--2023-09-12 15:27:40-- http://localhost:5000/test.json?f1[]
Resolving localhost (localhost)... 127.0.0.1
Connecting to localhost (localhost)|127.0.0.1|:5000... connected.
HTTP request sent, awaiting response... 400 Bad Request
2023-09-12 15:27:40 ERROR 400: Bad Request.