feat: recursive environment variable resolution

packages/hoppscotch-app/helpers/templating.ts

@@ -1,25 +1,87 @@
+import * as E from "fp-ts/Either"
+import { pipe } from "fp-ts/function"
 import { Environment } from "~/newstore/environments"
 
-export function parseBodyEnvVariables(
+const REGEX_ENV_VAR = /<<([^>]*)>>/g // "<<myVariable>>"
+
+/**
+ * How much times can we expand environment variables
+ */
+const ENV_MAX_EXPAND_LIMIT = 10
+
+/**
+ * Error state when there is a suspected loop while
+ * recursively expanding variables
+ */
+const ENV_EXPAND_LOOP = "ENV_EXPAND_LOOP" as const
+
+export function parseBodyEnvVariablesE(
   body: string,
   env: Environment["variables"]
 ) {
-  return body.replace(/<<\w+>>/g, (key) => {
-    const found = env.find((envVar) => envVar.key === key.replace(/[<>]/g, ""))
-    return found ? found.value : key
-  })
+  let result = body
+  let depth = 0
+
+  while (result.match(REGEX_ENV_VAR) != null && depth <= ENV_MAX_EXPAND_LIMIT) {
+    result = result.replace(/<<\w+>>/g, (key) => {
+      const found = env.find(
+        (envVar) => envVar.key === key.replace(/[<>]/g, "")
+      )
+      return found ? found.value : key
+    })
+
+    depth++
+  }
+
+  return depth > ENV_MAX_EXPAND_LIMIT
+    ? E.left(ENV_EXPAND_LOOP)
+    : E.right(result)
 }
 
-export function parseTemplateString(
+/**
+ * @deprecated Use `parseBodyEnvVariablesE` instead.
+ */
+export const parseBodyEnvVariables = (
+  body: string,
+  env: Environment["variables"]
+) =>
+  pipe(
+    parseBodyEnvVariablesE(body, env),
+    E.getOrElse(() => body)
+  )
+
+export function parseTemplateStringE(
   str: string,
   variables: Environment["variables"]
 ) {
   if (!variables || !str) {
-    return str
+    return E.right(str)
   }
-  const searchTerm = /<<([^>]*)>>/g // "<<myVariable>>"
-  return decodeURI(encodeURI(str)).replace(
-    searchTerm,
-    (_, p1) => variables.find((x) => x.key === p1)?.value || ""
-  )
+
+  let result = str
+  let depth = 0
+
+  while (result.match(REGEX_ENV_VAR) != null && depth <= ENV_MAX_EXPAND_LIMIT) {
+    result = decodeURI(encodeURI(result)).replace(
+      REGEX_ENV_VAR,
+      (_, p1) => variables.find((x) => x.key === p1)?.value || ""
+    )
+    depth++
+  }
+
+  return depth > ENV_MAX_EXPAND_LIMIT
+    ? E.left(ENV_EXPAND_LOOP)
+    : E.right(result)
 }
+
+/**
+ * @deprecated Use `parseTemplateStringE` instead
+ */
+export const parseTemplateString = (
+  str: string,
+  variables: Environment["variables"]
+) =>
+  pipe(
+    parseTemplateStringE(str, variables),
+    E.getOrElse(() => str)
+  )