I’m getting two spaces like this:

user=> (println (json/generate-string {:x 1 :y 2} {:pretty true}))
{
  "x" : 1,
  "y" : 2
}

https://github.com/dakrone/cheshire/blob/ceb3307468f80814a6d39d3007da70466575ae82/src/cheshire/core.clj#L17

https://github.com/dakrone/cheshire#custom-pretty-printing-options

Aaah, awesome! That’s exactly what I wanted. Thank you! 🙏

In case anyone else is interested, this is what I did:

(def -cheshire-pretty-printer
  (let [opts (assoc json/default-pretty-print-options
                    :indentation "    ")]
    (json/create-pretty-printer opts)))

(defn json-generate-string [x]
  (json/generate-string x {:pretty -cheshire-pretty-printer}))

Content-Type is a header

That's true, but didn't solve the issue I get Unhandled RuntimeException: Invalid token :

generally the fragment of clojure that is exchanged as a data serialization format is called "edn" and I don't believe there is a registered mime type for it, but I suspect application/edn is most used

what does the rest of the stacktrace say

Show: Project-Only All 
  Hide: Clojure Java REPL Tooling Duplicates  (33 frames hidden)

1. Unhandled java.lang.RuntimeException
   Invalid token: :

                 Util.java:  221  clojure.lang.Util/runtimeException
           LispReader.java:  412  clojure.lang.LispReader/interpretToken
           LispReader.java:  305  clojure.lang.LispReader/read
           LispReader.java: 1398  clojure.lang.LispReader/readDelimitedList
           LispReader.java: 1355  clojure.lang.LispReader$MapReader/invoke
           LispReader.java:  285  clojure.lang.LispReader/read
           LispReader.java: 1398  clojure.lang.LispReader/readDelimitedList
           LispReader.java: 1347  clojure.lang.LispReader$VectorReader/invoke
           LispReader.java:  285  clojure.lang.LispReader/read
           LispReader.java:  216  clojure.lang.LispReader/read
           LispReader.java:  205  clojure.lang.LispReader/read
                   RT.java: 1876  clojure.lang.RT/readString
                   RT.java: 1871  clojure.lang.RT/readString
                  core.clj: 3816  clojure.core/read-string
                  core.clj: 3806  clojure.core/read-string
                client.clj:  478  clj-http.client/coerce-clojure-body/fn
                client.clj:  477  clj-http.client/coerce-clojure-body
                client.clj:  470  clj-http.client/coerce-clojure-body
                client.clj:  545  clj-http.client/eval11811/fn
              MultiFn.java:  234  clojure.lang.MultiFn/invoke
                client.clj:  563  clj-http.client/output-coercion-response
                client.clj:  560  clj-http.client/output-coercion-response
                client.clj:  574  clj-http.client/wrap-output-coercion/fn
                client.clj:  250  clj-http.client/wrap-exceptions/fn
                client.clj:  728  clj-http.client/wrap-accept/fn
                client.clj:  750  clj-http.client/wrap-accept-encoding/fn
                client.clj:  711  clj-http.client/wrap-content-type/fn
                client.clj:  959  clj-http.client/wrap-form-params/fn
                client.clj:  993  clj-http.client/wrap-nested-params/fn
                client.clj: 1017  clj-http.client/wrap-flatten-nested-params/fn
                client.clj:  893  clj-http.client/wrap-method/fn
               cookies.clj:  128  clj-http.cookies/wrap-cookies/fn
                 links.clj:   63  clj-http.links/wrap-links/fn
                client.clj: 1046  clj-http.client/wrap-unknown-host/fn
                client.clj: 1174  clj-http.client/request*
                client.clj: 1167  clj-http.client/request*
                client.clj: 1180  clj-http.client/get
                client.clj: 1176  clj-http.client/get
               RestFn.java:  423  clojure.lang.RestFn/invoke
         message_store.clj:   49  server.message-store/get-conversations
         message_store.clj:   47  server.message-store/get-conversations
                      REPL:   55  server.message-store/eval14934
                      REPL:   55  server.message-store/eval14934
             Compiler.java: 7194  clojure.lang.Compiler/eval
             Compiler.java: 7149  clojure.lang.Compiler/eval
                  core.clj: 3215  clojure.core/eval
                  core.clj: 3211  clojure.core/eval
    interruptible_eval.clj:   87  nrepl.middleware.interruptible-eval/evaluate/fn/fn
                  AFn.java:  152  clojure.lang.AFn/applyToHelper
                  AFn.java:  144  clojure.lang.AFn/applyTo
                  core.clj:  667  clojure.core/apply
                  core.clj: 1990  clojure.core/with-bindings*
                  core.clj: 1990  clojure.core/with-bindings*
               RestFn.java:  425  clojure.lang.RestFn/invoke
    interruptible_eval.clj:   87  nrepl.middleware.interruptible-eval/evaluate/fn
                  main.clj:  437  clojure.main/repl/read-eval-print/fn
                  main.clj:  437  clojure.main/repl/read-eval-print
                  main.clj:  458  clojure.main/repl/fn
                  main.clj:  458  clojure.main/repl
                  main.clj:  368  clojure.main/repl
               RestFn.java: 1523  clojure.lang.RestFn/invoke
    interruptible_eval.clj:   84  nrepl.middleware.interruptible-eval/evaluate
    interruptible_eval.clj:   56  nrepl.middleware.interruptible-eval/evaluate
    interruptible_eval.clj:  152  nrepl.middleware.interruptible-eval/interruptible-eval/fn/fn
                  AFn.java:   22  clojure.lang.AFn/run
               session.clj:  218  nrepl.middleware.session/session-exec/main-loop/fn
               session.clj:  217  nrepl.middleware.session/session-exec/main-loop
                  AFn.java:   22  clojure.lang.AFn/run
               Thread.java: 1583  java.lang.Thread/run

Output of the API is an array in case that matters

Maybe EDN can't handle that, idk

that isn't going to work

:as :clojure basically means "call the clojure reader on the body of the response"

Why wouldn't that work but :json would?

because the api is replying with json encoded data not edn encoded data

the clojure reader doesn't read json

Got it. I thought the coercion meant there was some client-side code that literally coerced the data using some defaults into Clojure if possible

:json does that

Ohhh

So :clojure is more commonly used for clj <-> clj communciations then?

Since most APIs don't use Clojure as the data transfer format

https://github.com/edn-format/edn

for returns a lazy sequence, so you can write (first (for [... :when foo?] ...)) to stop after the first :when foo?

other common patterns for 'early return' include not recurring and using the reduced function (in the context of a reduce)

there are several methods to return early in function languages... most fundamentally using recursion

example of short-circuiting for https://raw.githubusercontent.com/samcf/advent-of-code/main/2020-01-report-repair.clj

it doesn't matter if for is lazy, or whatever, max has to traverse the whole thing, and you would have to traverse the whole thing to find max in python as well

finding the max for a sequence of numbers is not a good example for early returns, because it cannot return early

in this case, since the sequence starts in descending order, rather than building a sequence of zeroes, it would be possible to just filter that sequence to the elements where the divisor divides both subjects, and then the first thing in that list will be the max, so then the use of max becomes unnecessary, and the operation can be lazy-ish

yes, usage of the max function will become un-necessary if for is lazy and I can get some guarantee of the order of the sequence that is being generated by the for.

thanks for the pointers @U02FVPF04A1 @U013JFLRFS8 @U0NCTKEV8. This is good information for me as a beginner to Clojure.

For the original use case, (some my-function collection) will "short circuit". Recursive functions can stop when they like by not recurring. Beyond that, back in the good old days of Cobol I spent a couple of hours helping someone on an inexplicable bug. Finally in a daze I scrolled up a few pages. An early exit (above the fold so we did not see it) made the behavior explicable. :face_palm: