Payload Return Size

jzxchiang · August 31, 2021, 5:19am

Funny enough, I’m actually looking at this right now, and it’s your lucky day! Here are two examples:

This one’s in Motoko:

DepartureLabsIC/non-fungible-token/blob/1c183f38e2eea978ff0332cf6ce9d95b8ac1b43d/src/main.mo#L468

    
      
                          };
                      };
                  };
              };
              {
                  body  = Blob.fromArray([]);
                  token = null;
              };
          };
          
          
public query func http_request_streaming_callback(
              token : Http.StreamingCallbackToken
          ) : async Http.StreamingCallbackResponse {
              switch(nfts.getToken(token.key)) {
                  case (#err(_)) {
                      // TODO: also check static assets?
                      {
                          body  = Blob.fromArray([]); 
                          token = null;
                      };
                  };

This one’s in Rust:

github.com

dfinity/certified-assets/blob/b06c8a7a53fdb214596ba12cd10be8508b6f2192/src/lib.rs#L683

    
      
          
          
    let path = match req.url.find('?') {
                  Some(i) => &req.url[..i],
                  None => &req.url[..],
              };
          
          
    build_http_response(&url_decode(&path), encodings, 0)
          }
          
          
#[query]
          fn http_request_streaming_callback(
              StreamingCallbackToken {
                  key,
                  content_encoding,
                  index,
                  sha256,
              }: StreamingCallbackToken,
          ) -> StreamingCallbackHttpResponse {
              STATE.with(|s| {
                  let assets = s.assets.borrow();
                  let asset = assets

LevenSton · September 1, 2021, 3:31am

thanks so much!!
I wrote a motoko example , and deploy local, and then called a test function, put into 1 million data, and then queryed the data through the http_request interface
http://localhost:8000/?canisterId=rrkah-fqaaa-aaaaa-aaaaq-cai&/getAll
and got a error:
Replica Error (5): “IC0501: Canister rrkah-fqaaa-aaaaa-aaaaq-cai exceeded the cycles limit for single message execution.”

Do you have some experience。？ thanks!

skilesare · September 1, 2021, 11:02am

You may have to chunk it back out as well. Allocating arrays can be expensive. I store my chunks as chunks so they can go out the same way they came in.

Also, try buffers instead of arrays.

Array.append(first8MBk,next2MB) chews up a ton of cycles for allocation because you are making a whole new array each time.

eddy · September 10, 2021, 6:49am

Have you found a solution for big data reading now?

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Payload Return Size

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