feat: compute step parameters with prior steps

packages/backend/package.json

@@ -18,6 +18,7 @@
   "dependencies": {
     "@automatisch/web": "0.1.0",
     "@octokit/oauth-methods": "^1.2.6",
+    "@types/lodash.get": "^4.4.6",
     "axios": "0.24.0",
     "bcrypt": "^5.0.1",
     "cors": "^2.8.5",
@@ -32,6 +33,7 @@
     "graphql-type-json": "^0.3.2",
     "http-errors": "~1.6.3",
     "knex": "^0.95.11",
+    "lodash.get": "^4.4.2",
     "morgan": "^1.10.0",
     "nodemailer": "6.7.0",
     "objection": "^3.0.0",

packages/backend/src/graphql/mutations/create-flow.ts

@@ -1,7 +1,7 @@
 import Step from '../../models/step';
 import flowType, { flowInputType } from '../types/flow';
 import RequestWithCurrentUser from '../../types/express/request-with-current-user';
-import StepEnumType from '../../types/step-enum-type';
+import { StepType } from '../../types/step';
 
 type Params = {
   input: {
@@ -21,7 +21,7 @@ const createFlowResolver = async (
 
   await Step.query().insert({
     flowId: flow.id,
-    type: StepEnumType.Trigger,
+    type: StepType.Trigger,
     position: 1,
     appKey,
   });

packages/backend/src/graphql/mutations/create-step.ts

@@ -1,7 +1,7 @@
 import { GraphQLNonNull } from 'graphql';
 import stepType, { stepInputType } from '../types/step';
 import RequestWithCurrentUser from '../../types/express/request-with-current-user';
-import StepEnumType from '../../types/step-enum-type';
+import { StepType } from '../../types/step';
 
 type Params = {
   input: {
@@ -42,7 +42,7 @@ const createStepResolver = async (
   const step = await flow.$relatedQuery('steps').insertAndFetch({
     key: input.key,
     appKey: input.appKey,
-    type: StepEnumType.Action,
+    type: StepType.Action,
     position: previousStep.position + 1,
     parameters: {},
   });

packages/backend/src/models/step.ts

@@ -2,14 +2,14 @@ import Base from './base';
 import Flow from './flow';
 import Connection from './connection';
 import ExecutionStep from './execution-step';
-import StepEnumType from '../types/step-enum-type';
+import { StepType } from '../types/step';
 
 class Step extends Base {
   id!: number;
   flowId!: string;
   key: string;
   appKey: string;
-  type!: StepEnumType;
+  type!: StepType;
   connectionId?: string;
   status: string;
   position: number;

packages/backend/src/services/processor.ts

@@ -1,13 +1,19 @@
+import get from 'lodash.get';
 import App from '../models/app';
 import Flow from '../models/flow';
 import Step from '../models/step';
 import Execution from '../models/execution';
 import ExecutionStep from '../models/execution-step';
+import { StepType } from '../types/step';
+
+type ExecutionSteps = Record<string, ExecutionStep>;
 
 class Processor {
   flow: Flow;
   untilStep: Step;
 
+  static variableRegExp = /({{step\.\d*\..+?}})/g;
+
   constructor(flow: Flow, untilStep: Step) {
     this.flow = flow;
     this.untilStep = untilStep;
@@ -26,48 +32,71 @@ class Processor {
 
     let previousExecutionStep: ExecutionStep;
     let fetchedData;
+    const priorExecutionSteps: ExecutionSteps = {};
 
     for await (const step of steps) {
       const appData = App.findOneByKey(step.appKey);
+      const {
+        appKey,
+        connection,
+        key,
+        type,
+        parameters: rawParameters = {},
+        id
+      } = step;
+      const isTrigger = type === StepType.Trigger;
+      const AppClass = (await import(`../apps/${appKey}`)).default;
+      const computedParameters = Processor.computeParameters(rawParameters, priorExecutionSteps);
+      const appInstance = new AppClass(appData, connection.data, computedParameters);
+      const commands = isTrigger ? appInstance.triggers : appInstance.actions;
+      const command = commands[key];
+      fetchedData = await command.run();
 
-      if (step.type.toString() === 'trigger') {
-        const appClass = (await import(`../apps/${step.appKey}`)).default;
-        const appInstance = new appClass(appData, step.connection.data);
-        fetchedData = await appInstance.triggers[step.key].run();
+      previousExecutionStep = await execution
+        .$relatedQuery('executionSteps')
+        .insertAndFetch({
+          stepId: id,
+          status: 'success',
+          dataIn: previousExecutionStep?.dataOut,
+          dataOut: fetchedData,
+        });
 
-        previousExecutionStep = await execution
-          .$relatedQuery('executionSteps')
-          .insertAndFetch({
-            stepId: step.id,
-            status: 'success',
-            dataOut: fetchedData,
-          });
-      } else {
-        const appClass = (await import(`../apps/${step.appKey}`)).default;
-        const appInstance = new appClass(
-          appData,
-          step.connection.data,
-          step.parameters
-        );
-        fetchedData = await appInstance.actions[step.key].run();
+      priorExecutionSteps[id] = previousExecutionStep;
 
-        previousExecutionStep = await execution
-          .$relatedQuery('executionSteps')
-          .insertAndFetch({
-            stepId: step.id,
-            status: 'success',
-            dataIn: previousExecutionStep.dataOut,
-            dataOut: fetchedData,
-          });
-      }
-
-      if (step.id === this.untilStep.id) {
+      if (id === this.untilStep.id) {
         return fetchedData;
       }
     }
 
     return fetchedData;
   }
+
+  static computeParameters(parameters: Step["parameters"], executionSteps: ExecutionSteps): Step["parameters"] {
+    const entries = Object.entries(parameters);
+    return entries.reduce((result, [key, value]: [string, string]) => {
+      const parts = value.split(Processor.variableRegExp);
+
+      const computedValue = parts.map((part: string) => {
+        const isVariable = part.match(Processor.variableRegExp);
+        if (isVariable) {
+          const stepIdAndKeyPath = part.replace(/{{step.|}}/g, '') as string;
+          const [stepId, ...keyPaths] = stepIdAndKeyPath.split('.');
+          const keyPath = keyPaths.join('.');
+          const executionStep = executionSteps[stepId.toString() as string];
+          const data = executionStep?.dataOut;
+          const dataValue = get(data, keyPath);
+          return dataValue;
+        }
+
+        return part;
+      }).join('');
+
+      return {
+        ...result,
+        [key]: computedValue,
+      }
+    }, {});
+  }
 }
 
 export default Processor;

packages/backend/src/types/step-enum-type.ts

@@ -1,6 +0,0 @@
-enum StepEnumType {
-  Trigger = 'trigger',
-  Action = 'action',
-}
-
-export default StepEnumType;

packages/backend/src/types/step.ts

@@ -0,0 +1,4 @@
+export enum StepType {
+  Trigger = 'trigger',
+  Action = 'action',
+}

yarn.lock

@@ -4166,6 +4166,13 @@
   resolved "https://registry.yarnpkg.com/@types/json5/-/json5-0.0.29.tgz#ee28707ae94e11d2b827bcbe5270bcea7f3e71ee"
   integrity sha1-7ihweulOEdK4J7y+UnC86n8+ce4=
 
+"@types/lodash.get@^4.4.6":
+  version "4.4.6"
+  resolved "https://registry.yarnpkg.com/@types/lodash.get/-/lodash.get-4.4.6.tgz#0c7ac56243dae0f9f09ab6f75b29471e2e777240"
+  integrity sha512-E6zzjR3GtNig8UJG/yodBeJeIOtgPkMgsLjDU3CbgCAPC++vJ0eCMnJhVpRZb/ENqEFlov1+3K9TKtY4UdWKtQ==
+  dependencies:
+    "@types/lodash" "*"
+
 "@types/lodash.template@^4.5.0":
   version "4.5.0"
   resolved "https://registry.yarnpkg.com/@types/lodash.template/-/lodash.template-4.5.0.tgz#277654af717ed37ce2687c69f8f221c550276b7a"