feat: add pallets/dispatchables endpoint

[marshacb]

Summary: An endpoint that returns the dispatchables for a given pallet

/pallets/{palletId}/dispatchables

Query Params

• onlyIds: boolean to return only the Id of each dispatchable instead of the entirety of each dispatchable

Sample response for /pallets/democracy/dispatchables?onlyIds=true

{
	"at": {
		"hash": "0xf66741758c3b3dd5ed7ebac42b20d5f5d5a39f47ee5069c1ab5ffc5e1929428d",
		"height": "14045022"
	},
	"pallet": "democracy",
	"palletIndex": "14",
	"items": [
		"propose",
		"second",
		"vote",
		"emergencyCancel",
		"externalPropose",
		"externalProposeMajority",
		"externalProposeDefault",
		"fastTrack",
		"vetoExternal",
		"cancelReferendum",
		"delegate",
		"undelegate",
		"clearPublicProposals",
		"unlock",
		"removeVote",
		"removeOtherVote",
		"blacklist",
		"cancelProposal"
	]
}

/pallets/{palletId}/dispatchables/{dispatchableItemId}

Query Params

• metadata: boolean to choose whether to include a dispatchable's metadata in the response

Sample response for /pallets/democracy/dispatchables/propose

{
	"at": {
		"hash": "0x96a6c2e87fe3b2e1b367c56299287bdf10811cc39656e92afd3db15aad7feda4",
		"height": "14046525"
	},
	"pallet": "democracy",
	"palletIndex": "14",
	"dispatchableItem": "propose"
}

[TarikGul]

Giving this a thumbs up even though I requested for review, that was by accident (until I realized we had discussed about that at query param before).

Just some small nits, and comments but overall great job!

[Imod7]

Amazing work as always! 💯 I added some comments and suggestions that I think are quick fixes! 🙏

And I have two additional questions :

1. For the endpoint http://127.0.0.1:8080/pallets/53/dispatchables (connected to polkadot) why the calls are an empty array ?

   {
     "at": {
       "hash": "0x726844aacf88c26d62dab9506e10fa6a943f6bd850c557c14d5179dba9618744",
       "height": "14430205"
     },
     "pallet": "paraInclusion",
     "palletIndex": "53",
     "items": []
   }
   

   It is not an error since in polkadot parachains inclusion it looks like it is also empty. I was just wondering what is the use of this empty array.

2. It is not related to the dispatchables endpoint so if it is out of scope of this PR please let me know and I will address it at another place. For the storage endpoint :
   http://127.0.0.1:8080/pallets/authorityDiscovery/storage
   I get an error

   {
     "code": 400,
     "message": "no queryable storage items found for palletId \"authorityDiscovery\"",
     "stack": "BadRequestError: no queryable storage items found for palletId \"authorityDiscovery\"\n    at PalletsStorageService.findPalletMeta (/Users/tiny_imod/Documents/Parity/substrate-api-sidecar/build/src/services/AbstractPalletsService.js:94:19)\n    at PalletsStorageService.fetchStorage (/Users/tiny_imod/Documents/Parity/substrate-api-sidecar/build/src/services/pallets/PalletsStorageService.js:92:50)\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)\n    at async PalletsStorageController.getStorage (/Users/tiny_imod/Documents/Parity/substrate-api-sidecar/build/src/controllers/pallets/PalletsStorageController.js:65:57)\n    at async /Users/tiny_imod/Documents/Parity/substrate-api-sidecar/build/src/controllers/AbstractController.js:226:9",
     "level": "error"
   }
   

   while connected to polkadot. But in Substrate under Authority Discovery pallet I can find two storage items, keys and nextKeys. When I also tried to retrieve those storage items from pjs-api (docs) with api.query.authorityDiscovery.keys it does not work either. I was wondering why.

Thank you so much!!! 🙏

[CurlyBracketEffect]

Nice Work!

[marshacb]

Amazing work as always! 💯 I added some comments and suggestions that I think are quick fixes! 🙏

And I have two additional questions :

1. For the endpoint http://127.0.0.1:8080/pallets/53/dispatchables (connected to polkadot) why the calls are an empty array ?

   {
     "at": {
       "hash": "0x726844aacf88c26d62dab9506e10fa6a943f6bd850c557c14d5179dba9618744",
       "height": "14430205"
     },
     "pallet": "paraInclusion",
     "palletIndex": "53",
     "items": []
   }
   

   It is not an error since in polkadot parachains inclusion it looks like it is also empty. I was just wondering what is the use of this empty array.

2. It is not related to the dispatchables endpoint so if it is out of scope of this PR please let me know and I will address it at another place. For the storage endpoint :
   http://127.0.0.1:8080/pallets/authorityDiscovery/storage
   I get an error

   {
     "code": 400,
     "message": "no queryable storage items found for palletId \"authorityDiscovery\"",
     "stack": "BadRequestError: no queryable storage items found for palletId \"authorityDiscovery\"\n    at PalletsStorageService.findPalletMeta (/Users/tiny_imod/Documents/Parity/substrate-api-sidecar/build/src/services/AbstractPalletsService.js:94:19)\n    at PalletsStorageService.fetchStorage (/Users/tiny_imod/Documents/Parity/substrate-api-sidecar/build/src/services/pallets/PalletsStorageService.js:92:50)\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)\n    at async PalletsStorageController.getStorage (/Users/tiny_imod/Documents/Parity/substrate-api-sidecar/build/src/controllers/pallets/PalletsStorageController.js:65:57)\n    at async /Users/tiny_imod/Documents/Parity/substrate-api-sidecar/build/src/controllers/AbstractController.js:226:9",
     "level": "error"
   }
   

   while connected to polkadot. But in Substrate under Authority Discovery pallet I can find two storage items, keys and nextKeys. When I also tried to retrieve those storage items from pjs-api (docs) with api.query.authorityDiscovery.keys it does not work either. I was wondering why.

Thank you so much!!! 🙏

I'm not exactly sure why this is empty in the polkadot codebase. Ill make a note and see if I can find a reason at some point.

As for the storage question I have no idea at the moment. Since polkadot js also doesnt show those items I assume its for a reason but we probably need to check it out in more detail.

[Imod7]

Approved witrh 2 small corrections to make (as mentioned below) :

1. in the docs and
2. removal of debugging statement

and 3 additional notes :

1. I think it is worth adding a break; statement also in the errors and events loop so right after this line and this line respectively since the loop continues in the whole list of entries even if it finds the entry requested. So the same correction that was applied for the dispatchables.
2. By reading Tarik s comment, it looks like there is a reason for not having the query param at in both dispatchables endpoints. However, I could not find a comment (as Tarik mentioned) that explains the why. It would be really useful to have an explanation if possible. 🙏
3. Also, in the description of this PR in the section /pallets/{palletId}/dispatchables/{dispatchableItemId} it mentions query param at. If we do not have it maybe we could update the description by removing it ?