HTLC database APIs

[abitmore]

User Story
As a user / client developer I want database APIs to query for active HTLC objects.

• One API to list all HTLC objects.
• APIs to by account, perhaps 2 APIs, one query by from, one query by to.
• Pagination should be considered.
• Perhaps by default order by expiration?
• Perhaps let get_full_accounts API return HTLC objects as well.
• Best have CLI commands as well.

UI work is blocked by this.

Impacts
Describe which portion(s) of BitShares Core may be impacted by your request. Please tick at least one box.

• API (the application programming interface)
• Build (the build process or something prior to compiled code)
• CLI (the command line wallet)
• Deployment (the deployment process after building such as Docker, Travis, etc.)
• DEX (the Decentralized EXchange, market engine, etc.)
• P2P (the peer-to-peer network for transaction/block propagation)
• Performance (system or user efficiency, etc.)
• Protocol (the blockchain logic, consensus, validation, etc.)
• Security (the security of system or user data, etc.)
• UX (the User Experience)
• Other (please add below)

Additional Context (optional)
Add any other context about your request here.

CORE TEAM TASK LIST

• Evaluate / Prioritize Feature Request
• Refine User Stories / Requirements
• Define Test Cases
• Design / Develop Solution
• Perform QA/Testing
• Update Documentation

[oxarbitrage]

I am interested on this one.

Question: Do we want to add the API calls in in database.cpp or do we want to create a new(enabled or disabled by default) htlc_api in api.cpp?

[pmconrad]

IMO database.cpp, but please use consistent naming.

[syalon]

Is it possible to provide an api for query by hashvalue?

[syalon]

In addition, preimage length is too unfriendly for users.

[syalon]

MobileApp requirements:

• get_full_accounts returns all relevant htlc, including from and to.
• query by hash (if possible)
• preimage length (can omit the best). Is this just for quick verification?

[abitmore]

In addition, preimage length is too unfriendly for users.

Perhaps we can make preimage_size effectively optional, e.g. if size==0, don't check the size. Need a BSIP.

[jmjatlanta]

The majority of these requests have been fixed by #1742. Others are being considered (i.e. sorting), and still others would require a BSIP (i.e. making preimage length optional).

[abitmore]

Lack of an API to fetch all HTLCs. See #1749 (comment). Moving to next milestone.

[abitmore]

Merged #1849. If need a CLI command, create a new issue.