Let’s say I have a contract A that’s supposed to be called from the frontend (DApp/TWA), and the full interaction involves several contracts: A calls B, C, D, and C again. It’s desirable to report on frontend whether the whole “saga” was successful. Is this feasible in TON without extra means (like backend/indexing APIs)?
A ---> B C D
| * | |
| <--- | | |
* | | |
| ---------> | |
| | * |
| <--------- | | // this may be missing if C is third-party
* | | |
| ---------------> |
| | | *
| <--------------- |
* | | |
| ---------> | |
| | * |
| <--------- | | // this may be missing if C is third-party
* | | |
The complication I see is that once A calls B, the initial tx from the user’s wallet is finished, and the rest of the process is done in new txs (tx 2: B recieves msg from A, computes, and sends another msg to A), which can’t bounce “back to wallet”, while in each compute point (* on the diagram) errors may take place. I’m aware that one can send and resend the same query_id for all the messages of this “saga”, but what’s the typical approach to error handling, especially when, say, contract C is a third-party one?
I’ve checked the article by Tal Kol that explains contract sharding and followed “User story 1” (sending Jetton), but the code is not self-explanatory: (ok, let’s skip the external messages stuff) what does the “revert on errors” comment mean? In my tests, if send_raw_message fails on the action phase, the code after it still computes (and that’s understandable, as it’s executed during the compute phase).
Basically my question is: how can I “collect” the results and “report” them on frontend (i.e. distinguish “pending”, “success”, and “failure” states)? In sandbox (Blueprint autotests), it’s simple: each send_ method of a SandboxContract returns a full log containing all the txs and events in the chain of interactions, but is there something similar available for frontend?