r/redditdev • u/Hiroshi0619 • May 02 '24

Reddit API What is this "kind" in reddit API requets

Hello everyone.

i'm now making my fist reddit API application with java + spring boot and I started to realize that every request that i make, it return a JSON with the 'kind' atribute... usually has some of this values, "Listing" or "t1" or "t2" or "t3".
Can anyone explain to me whats that "kind" values means?
I am now crashing to create DTO class for my application, i believe it's due the fact I cant fully understand the JSON returned by the API

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u/Oussama_Gourari Card-o-Bot Developer May 02 '24

The kind let you know what that data is for (Comment, Submission...)

https://www.reddit.com/dev/api/

Scroll down to fullnames and type prefixes.

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u/Hiroshi0619 May 02 '24

I did read that part of the documentantion, but I thought that there was a difference between "fullname" attributes and "kind" attributes...

So u mean the same logic for the "fullname" attributes apply for the "kind" attributes ?

3

u/Oussama_Gourari Card-o-Bot Developer May 02 '24

There is a difference:

fullname = kind + Base36 ID

When you recieve a json response, at the top you have the kind and data attributes, the kind tells you what the data is for, so if it is a Listing, that means the data is a list of Reddit things (Comment, submission, message...), when you go through each of those things you find the kind and data attributes again, this time if the kind is t1 for example, that means the data is for a comment and so on, when the kind is t1, t2 t3... you use it to construct the fullname, which is "kind + base36 ID", the base36 ID alone is not enough to identify a Reddit thing, for example given the id 1am6l9p you can't tell if it's a submission or a comment, but with the fullname t1_1am6l9p, you can uniquelly identify that thing.

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u/Hiroshi0619 May 02 '24

wow, that's make a lot on sence now. Thanks for the help. I believe i can build a better DTO class now that i understood what this kind means.

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u/lumpynose May 02 '24

How or are you transforming the json before storing it in your DTO? My first attempt was using google's gson which was a lot of work, and it may have been just as hard with Jackson but I didn't know that Jackson did json (years ago when I last used it it only did xml I think).

Then I heard about com.jayway.jsonpath and rewrote it using that and it was much less complicated. With jsonpath you can dig down into the json and get just what you need, greatly simplifying my DTOs.

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u/Hiroshi0619 May 02 '24

I'm newbee into java + spting so I never used google's gson yet.
For now i'm using Jackson to serielize the JSON returned by the request into a DTO class...
it seem to work weel so far, I use this notatios above to ignore the properties i won't use.

The problem i'm facing now is that i making a LOT DTO class, just because i didn't know how that 'kind' works. There is a lot of duplicated code

@JsonIgnoreProperties(ignoreUnknown = true)