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wasm_query/3

Module​

This predicate is provided by wasm.pl.

Load this module before using the predicate:

:- consult('/v1/lib/wasm.pl').

Description​

Executes a CosmWasm smart query against the contract at Address.

  • Address must be a valid Bech32 account address.
  • RequestBytes is the exact query payload as bytes (typically UTF-8 JSON).
  • ResponseBytes is unified with the raw response bytes returned by the contract.

Both RequestBytes and ResponseBytes use lists of integers in [0,255].

Signature​

wasm_query(+Address, +RequestBytes, -ResponseBytes) is det

Examples​

Query a smart contract and read raw response bytes​

This scenario demonstrates how to send a smart-query payload as bytes and get the raw response bytes back.

Here are the steps of the scenario:

  • Given the CosmWasm smart contract "axone15ekvz3qdter33mdnk98v8whv5qdr53yusksnfgc08xd26fpdn3tsrhsdrk" and the behavior:
message: |
  {"ping":"pong"}
response: |
  {"ok":true}
  • Given the program:
:- consult('/v1/lib/wasm.pl').
  • Given the query:
wasm_query(
  'axone15ekvz3qdter33mdnk98v8whv5qdr53yusksnfgc08xd26fpdn3tsrhsdrk',
  [123,34,112,105,110,103,34,58,34,112,111,110,103,34,125],
  ResponseBytes
).
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 16085
answer:
  has_more: false
  variables: ["ResponseBytes"]
  results:
  - substitutions:
    - variable: ResponseBytes
      expression: "[123,34,111,107,34,58,116,114,117,101,125]"

Reject an invalid contract address​

This scenario demonstrates how wasm_query/3 validates the contract address format before calling the chain.

Here are the steps of the scenario:

  • Given the program:
:- consult('/v1/lib/wasm.pl').
  • Given the query:
wasm_query('invalid-address', [123,125], ResponseBytes).
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 9193
answer:
  has_more: false
  variables: ["ResponseBytes"]
  results:
  - error: "error(domain_error(valid_encoding(bech32),invalid-address),wasm_query/3)"

Reject a non-byte request payload​

This scenario demonstrates how wasm_query/3 raises a type error when the payload list contains values outside the byte range [0,255].

Here are the steps of the scenario:

  • Given the program:
:- consult('/v1/lib/wasm.pl').
  • Given the query:
wasm_query(
  'axone15ekvz3qdter33mdnk98v8whv5qdr53yusksnfgc08xd26fpdn3tsrhsdrk',
  [256],
  ResponseBytes
).
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 11151
answer:
  has_more: false
  variables: ["ResponseBytes"]
  results:
  - error: "error(type_error(byte,256),wasm_query/3)"

Surface contract query execution failures​

This scenario demonstrates that a contract query failure is surfaced as a system error in wasm_query/3.

Here are the steps of the scenario:

  • Given the CosmWasm smart contract "axone15ekvz3qdter33mdnk98v8whv5qdr53yusksnfgc08xd26fpdn3tsrhsdrk" and the behavior:
message: |
  {"ping":"pong"}
error: wasm contract execution failed
  • Given the program:
:- consult('/v1/lib/wasm.pl').
  • Given the query:
wasm_query(
  'axone15ekvz3qdter33mdnk98v8whv5qdr53yusksnfgc08xd26fpdn3tsrhsdrk',
  [123,34,112,105,110,103,34,58,34,112,111,110,103,34,125],
  ResponseBytes
).
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 15041
answer:
  has_more: false
  variables: ["ResponseBytes"]
  results:
  - error: "error(system_error,wasm_query/3)"