Forum OpenACS Development: Re: From database to JSON

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9: Re: From database to JSON (response to 8)
Posted by Brian Fenton on 09/28/23 03:28 PM
This looks very good. I particularly like the type support, which is badly missing in util::json
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10: Re: From database to JSON (response to 9)
Posted by Neophytos Demetriou on 09/28/23 03:34 PM
You can see more object or array manipulation commands in this example.

I will add a create command though. Thanks for that.

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11: Re: From database to JSON (response to 9)
Posted by Antonio Pisano on 09/28/23 03:40 PM
tDOM also offers explicity JSON type support, see e.g. jsonType at [1]

One advantage of using tDOM is that OpenACS already depends on it, so there is no extra library to load. Plus, cross-platform compatibility is already sorted out.

[1] http://tdom.org/index.html/doc/trunk/doc/domNode.html

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12: Re: From database to JSON (response to 11)
Posted by Neophytos Demetriou on 09/28/23 03:54 PM
I see your point but it does not support arrays, e.g. [1,2,3] or ["a","b","c"]. tdom does not parse it into anything. I tried it before I built tjson.
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14: Re: From database to JSON (response to 12)
Posted by Antonio Pisano on 09/28/23 04:24 PM
I have just tried this in a development shell:

dom parse -json {[1,2,3]} test
$test asJSON

-->

[1,2,3]

so it seems that the parsing has worked. Can you provide an example where tDOM fails to parse a valid JSON?

Ciao

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15: Re: From database to JSON (response to 14)
Posted by Neophytos Demetriou on 09/28/23 04:42 PM
I stand corrected.
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13: Re: From database to JSON (response to 11)
Posted by Neophytos Demetriou on 09/28/23 03:56 PM
Another way is to write the result to a csv and then exec python to convert it to json. The following line should work:

set result [exec -ignorestderr python3.10 -c "import csv, json, sys; print(json.dumps(\[dict(r) for r in csv.DictReader(sys.stdin)\]))" < /path/to/data.csv]
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16: Re: From database to JSON (response to 11)
Posted by Neophytos Demetriou on 09/28/23 06:21 PM
Can you provide an example where tDOM fails to parse a valid JSON?

Please download this file: https://raw.githubusercontent.com/stripe/openapi/master/openapi/spec3.json

and then run:


package require tdom
set fp [open "spec3.json"]
set data [read $fp]
close $fp
puts [time "dom parse -json $data test" 1

I get: error "JSON syntax error" at position 15

tjson runs fine with it:


package require tjson
set fp [open "spec3.json"]
set data [read $fp]
close $fp
puts [time "::tjson::parse $data" 1]

=> 18316 microseconds for tjson

It's probably something that I am doing wrong. Please let me know if you have better luck with it.

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17: Re: From database to JSON (response to 16)
Posted by Antonio Pisano on 09/29/23 01:12 AM

Hi Neophytos,

I have tried the following on my test vanilla instance:

set fp [open "/tmp/spec3.json" r]
set data [read $fp]
close $fp
lappend results [time {dom parse -json $data test} 1] [$test asJSON]

And the result was:

{23639 microseconds per iteration} {{"components":{"schemas":... (truncated)

The problem was the double quotes in

"dom parse -json $data test"

the $data JSON is expanded into the command string and won't be valid anymore.

Ciao

Antonio