update get-filetype to use known list of compressed extnames

packages/app-builder-lib/src/publish/KeygenPublisher.ts

@@ -4,6 +4,7 @@ import { ClientRequest, RequestOptions } from "http"
 import { HttpPublisher, PublishContext } from "electron-publish"
 import { KeygenOptions } from "builder-util-runtime/out/publishOptions"
 import { configureRequestOptions, HttpExecutor, parseJson } from "builder-util-runtime"
+import * as path from "path"
 
 export class KeygenPublisher extends HttpPublisher {
   readonly providerName = "keygen"
@@ -118,30 +119,30 @@ export class KeygenPublisher extends HttpPublisher {
   // e.g. `zip`, `dmg`, `tar.gz`, `tar.bz2`, `exe.blockmap`. We'd use `path.extname()`,
   // but it doesn't support multiple extensions, e.g. `dmg.blockmap`.
   private getFiletype(filename: string): string {
-    const components = filename
-      .split(".")
-      .filter(c => c !== "")
-      .slice(1)
-      .reverse()
-    const extnames = []
-    const regex = new RegExp(
-      "^" + // Test from start of string.
-        "(?=.*?[a-z])" + // Must contain at least 1 lowercase letter.
-        "(?=.*?[0-9]?)" + // May contain optional numbers.
-        "[a-z0-9]+" + // Must contain only lowercase letters and numbers.
-        "$" // Test to end of string.
-    )
+    let extname = path.extname(filename)
+
+    switch (extname) {
+      // Append leading extension for blockmap filetype
+      case '.blockmap': {
+        extname = path.extname(filename.replace(extname, '')) + extname
 
-    // Collect extensions, working backwards until we reach a non-extension.
-    for (const component of components) {
-      if (!regex.test(component)) {
-        // We've reached a non-extension (i.e. we've collected all valid extensions).
         break
       }
+      // Append leading extension for known compressed tar formats
+      case '.bz2':
+      case '.gz':
+      case '.lz':
+      case '.xz':
+      case '.7z': {
+        const ext = path.extname(filename.replace(extname, ''))
+        if (ext === '.tar') {
+          extname = ext + extname
+        }
 
-      extnames.unshift(component)
+        break
+      }
     }
 
-    return extnames.join(".")
+    return extname
   }
 }