A Metamask fork with Infura removed and default networks editable
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ciphermask/app/scripts/lib/rpc-method-middleware/createMethodMiddleware.js

110 lines
3.2 KiB

///: BEGIN:ONLY_INCLUDE_IN(flask)
import { handlers as permittedSnapMethods } from '@metamask/rpc-methods/dist/permitted';
///: END:ONLY_INCLUDE_IN
import { permissionRpcMethods } from '@metamask/controllers';
import { selectHooks } from '@metamask/rpc-methods/dist/utils';
import { ethErrors } from 'eth-rpc-errors';
import { flatten } from 'lodash';
import { UNSUPPORTED_RPC_METHODS } from '../../../../shared/constants/network';
import localHandlers from './handlers';
const allHandlers = [...localHandlers, ...permissionRpcMethods.handlers];
const handlerMap = allHandlers.reduce((map, handler) => {
for (const methodName of handler.methodNames) {
map.set(methodName, handler);
}
return map;
}, new Map());
const expectedHookNames = Array.from(
new Set(
flatten(allHandlers.map(({ hookNames }) => Object.keys(hookNames))),
).values(),
);
/**
* Creates a json-rpc-engine middleware of RPC method implementations.
*
* Handlers consume functions that hook into the background, and only depend
* on their signatures, not e.g. controller internals.
*
* @param {Record<string, unknown>} hooks - Required "hooks" into our
* controllers.
* @returns {(req: object, res: object, next: Function, end: Function) => void}
*/
export function createMethodMiddleware(hooks) {
// Fail immediately if we forgot to provide any expected hooks.
const missingHookNames = expectedHookNames.filter(
(hookName) => !Object.hasOwnProperty.call(hooks, hookName),
);
if (missingHookNames.length > 0) {
throw new Error(
`Missing expected hooks:\n\n${missingHookNames.join('\n')}\n`,
);
}
return async function methodMiddleware(req, res, next, end) {
// Reject unsupported methods.
if (UNSUPPORTED_RPC_METHODS.has(req.method)) {
return end(ethErrors.rpc.methodNotSupported());
}
const handler = handlerMap.get(req.method);
if (handler) {
const { implementation, hookNames } = handler;
try {
// Implementations may or may not be async, so we must await them.
return await implementation(
req,
res,
next,
end,
selectHooks(hooks, hookNames),
);
} catch (error) {
console.error(error);
return end(error);
}
}
return next();
};
}
///: BEGIN:ONLY_INCLUDE_IN(flask)
const snapHandlerMap = permittedSnapMethods.reduce((map, handler) => {
for (const methodName of handler.methodNames) {
map.set(methodName, handler);
}
return map;
}, new Map());
export function createSnapMethodMiddleware(isSnap, hooks) {
return async function methodMiddleware(req, res, next, end) {
const handler = snapHandlerMap.get(req.method);
if (handler) {
if (/^snap_/iu.test(req.method) && !isSnap) {
return end(ethErrors.rpc.methodNotFound());
}
const { implementation, hookNames } = handler;
try {
// Implementations may or may not be async, so we must await them.
return await implementation(
req,
res,
next,
end,
selectHooks(hooks, hookNames),
);
} catch (error) {
console.error(error);
return end(error);
}
}
return next();
};
}
///: END:ONLY_INCLUDE_IN