refactor: body type transition to ruleset based system

packages/hoppscotch-app/helpers/rules/BodyTransition.ts

@@ -0,0 +1,196 @@
+/**
+ * Defines how body should be updated for movement between different
+ * content-types
+ */
+
+import { pipe } from "fp-ts/function"
+import * as A from "fp-ts/Array"
+import {
+  FormDataKeyValue,
+  HoppRESTReqBody,
+  ValidContentTypes,
+} from "@hoppscotch/data"
+import {
+  parseRawKeyValueEntries,
+  rawKeyValueEntriesToString,
+  RawKeyValueEntry,
+} from "../rawKeyValue"
+
+const ANY_TYPE = Symbol("TRANSITION_RULESET_IGNORE_TYPE")
+// eslint-disable-next-line no-redeclare
+type ANY_TYPE = typeof ANY_TYPE
+
+type BodyType<T extends ValidContentTypes | null | ANY_TYPE> =
+  T extends ValidContentTypes
+    ? HoppRESTReqBody & { contentType: T }
+    : HoppRESTReqBody
+
+type TransitionDefinition<
+  FromType extends ValidContentTypes | null | ANY_TYPE,
+  ToType extends ValidContentTypes | null | ANY_TYPE
+> = {
+  from: FromType
+  to: ToType
+  definition: (
+    currentBody: BodyType<FromType>,
+    targetType: BodyType<ToType>["contentType"]
+  ) => BodyType<ToType>
+}
+
+const rule = <
+  FromType extends ValidContentTypes | null | ANY_TYPE,
+  ToType extends ValidContentTypes | null | ANY_TYPE
+>(
+  input: TransitionDefinition<FromType, ToType>
+) => input
+
+// Use ANY_TYPE to ignore from/dest type
+// Rules apply from top to bottom
+const transitionRuleset = [
+  rule({
+    from: null,
+    to: "multipart/form-data",
+    definition: () => ({
+      contentType: "multipart/form-data",
+      body: [],
+    }),
+  }),
+  rule({
+    from: ANY_TYPE,
+    to: null,
+    definition: () => ({
+      contentType: null,
+      body: null,
+    }),
+  }),
+  rule({
+    from: null,
+    to: ANY_TYPE,
+    definition: (_, targetType) => ({
+      contentType: targetType as unknown as Exclude<
+        // This is guaranteed by the above rules, we just can't tell TS this
+        ValidContentTypes,
+        "multipart/form-data"
+      >,
+      body: "",
+    }),
+  }),
+  rule({
+    from: "multipart/form-data",
+    to: "application/x-www-form-urlencoded",
+    definition: (currentBody, targetType) => ({
+      contentType: targetType,
+      body: pipe(
+        currentBody.body,
+        A.map(
+          ({ key, value, isFile, active }) =>
+            <RawKeyValueEntry>{
+              key,
+              value: isFile ? "" : value,
+              active,
+            }
+        ),
+        rawKeyValueEntriesToString
+      ),
+    }),
+  }),
+  rule({
+    from: "application/x-www-form-urlencoded",
+    to: "multipart/form-data",
+    definition: (currentBody, targetType) => ({
+      contentType: targetType,
+      body: pipe(
+        currentBody.body,
+        parseRawKeyValueEntries,
+        A.map(
+          ({ key, value, active }) =>
+            <FormDataKeyValue>{
+              key,
+              value,
+              active,
+              isFile: false,
+            }
+        )
+      ),
+    }),
+  }),
+  rule({
+    from: ANY_TYPE,
+    to: "multipart/form-data",
+    definition: () => ({
+      contentType: "multipart/form-data",
+      body: [],
+    }),
+  }),
+  rule({
+    from: "multipart/form-data",
+    to: ANY_TYPE,
+    definition: (_, target) => ({
+      contentType: target as Exclude<ValidContentTypes, "multipart/form-data">,
+      body: "",
+    }),
+  }),
+  rule({
+    from: "application/x-www-form-urlencoded",
+    to: ANY_TYPE,
+    definition: (_, target) => ({
+      contentType: target as Exclude<ValidContentTypes, "multipart/form-data">,
+      body: "",
+    }),
+  }),
+  rule({
+    from: ANY_TYPE,
+    to: "application/x-www-form-urlencoded",
+    definition: () => ({
+      contentType: "application/x-www-form-urlencoded",
+      body: "",
+    }),
+  }),
+  rule({
+    from: ANY_TYPE,
+    to: ANY_TYPE,
+    definition: (curr, targetType) => ({
+      contentType: targetType as Exclude<
+        // Above rules ensure this will be the case
+        ValidContentTypes,
+        "multipart/form-data" | "application/x-www-form-urlencoded"
+      >,
+      // Again, above rules ensure this will be the case, can't convince TS tho
+      body: (
+        curr as HoppRESTReqBody & {
+          contentType: Exclude<
+            ValidContentTypes,
+            "multipart/form-data" | "application/x-www-form-urlencoded"
+          >
+        }
+      ).body,
+    }),
+  }),
+] as const
+
+export const applyBodyTransition = <T extends ValidContentTypes | null>(
+  current: HoppRESTReqBody,
+  target: T
+): HoppRESTReqBody & { contentType: T } => {
+  debugger
+
+  if (current.contentType === target) {
+    console.warn(
+      `Tried to transition body from and to the same content-type '${target}'`
+    )
+    return current as any
+  }
+
+  const transitioner = transitionRuleset.find(
+    (def) =>
+      (def.from === current.contentType || def.from === ANY_TYPE) &&
+      (def.to === target || def.to === ANY_TYPE)
+  )
+
+  if (!transitioner) {
+    throw new Error("Body Type Transition Ruleset is invalid :(")
+  }
+
+  // TypeScript won't be able to figure this out easily :(
+  return (transitioner.definition as any)(current, target)
+}

packages/hoppscotch-app/helpers/typeutils.ts

@@ -12,6 +12,9 @@ export const objectFieldIncludes = <
   field: K,
   values: V
   // eslint-disable-next-line
-): obj is T & { [_x in K]: V[number] } => {
-  return values.includes(obj[field])
-}
+): obj is T & { [_x in K]: V[number] } => values.includes(obj[field])
+
+export const valueIncludes = <T, V extends readonly T[]>(
+  obj: T,
+  values: V
+): obj is V[number] => values.includes(obj)