Install a Snap From NPM iOS

- Create NPMLocation class
- Create a custom fetch function for the npm logic as we have slightly
  different logic
- create a swift native module to read a .tgz file and decompress it
- read the decompressed folder data and pass it to snaps

app/components/Views/Snaps/SnapsDev.tsx

@@ -20,15 +20,15 @@ import { createStyles } from './styles';
  *
  * local:http://localhost:3000/snap/
  * local:http://localhost:3000/helloworldsnap/
+ * npm:@consensys/starknet-snap
+ * npm:@chainsafe/filsnap
  */
 
 const SnapsDev = () => {
   const navigation = useNavigation();
   const { colors } = useTheme();
 
-  const [snapInput, setSnapInput] = useState<string>(
-    'local:http://localhost:3000/helloworldsnap/',
-  );
+  const [snapInput, setSnapInput] = useState<string>('npm:@chainsafe/filsnap');
   const snaps = useSelector(
     (state: any) => state.engine.backgroundState.SnapController.snaps,
   );

app/core/Snaps/SnapDuplex.ts

@@ -51,12 +51,7 @@ export default abstract class SnapDuplex extends Duplex {
 
   _write(data: StreamData, _encoding: string | null, cb: () => void): void {
     // eslint-disable-next-line no-console
-    console.log(
-      '[SNAP DUPLEX LOG] SnapDuplex+_write: Job',
-      this._jobId,
-      'write data (keys)',
-      Object.keys(data.data),
-    );
+    console.log('[SNAP DUPLEX LOG] SnapDuplex+_write: Job', this._jobId);
     this._stream.write({ data, jobId: this._jobId });
     cb();
   }

app/core/Snaps/location/http.ts

@@ -4,7 +4,9 @@ import {
   NpmSnapFileNames,
   createSnapManifest,
   normalizeRelative,
+  HttpSnapIdStruct,
 } from '@metamask/snaps-utils';
+import { assert, assertStruct } from '@metamask/utils';
 
 import { SnapLocation } from './location';
 
@@ -37,8 +39,7 @@ export class HttpLocation implements SnapLocation {
   private readonly fetchOptions?: RequestInit;
 
   constructor(url: URL, opts: HttpOptions = {}) {
-    // TODO get the asserts working from @metamask/utils
-    // assertStruct(url.toString(), HttpSnapIdStruct, 'Invalid Snap Id: ');
+    assertStruct(url.toString(), HttpSnapIdStruct, 'Invalid Snap Id: ');
     this.fetchFn = opts.fetch ?? globalThis.fetch.bind(globalThis);
     this.fetchOptions = opts.fetchOptions;
     this.url = url;
@@ -89,12 +90,11 @@ export class HttpLocation implements SnapLocation {
     });
 
     const blob = await response.text();
+    assert(
+      !this.cache.has(relativePath),
+      'Corrupted cache, multiple files with same path.',
+    );
 
-    //TODO: get the asserts working from @metamask/utils
-    // assert(
-    //   !this.cache.has(relativePath),
-    //   'Corrupted cache, multiple files with same path.',
-    // );
     this.cache.set(relativePath, { file: vfile, contents: blob });
 
     return this.fetch(relativePath);
@@ -105,8 +105,7 @@ export class HttpLocation implements SnapLocation {
   }
 
   private toCanonical(path: string): URL {
-    // TODO get the asserts working from @metamask/utils
-    // assert(!path.startsWith('/'), 'Tried to parse absolute path.');
+    assert(!path.startsWith('/'), 'Tried to parse absolute path.');
     return new URL(path, this.url.toString());
   }
 }

app/core/Snaps/location/local.ts

@@ -3,22 +3,22 @@ import {
   SnapIdPrefixes,
   SnapManifest,
   VirtualFile,
+  LocalSnapIdStruct,
 } from '@metamask/snaps-utils';
-
 import { HttpLocation, HttpOptions } from './http';
 import { SnapLocation } from './location';
+import { assert, assertStruct } from '@metamask/utils';
 
 export class LocalLocation implements SnapLocation {
   readonly #http: HttpLocation;
 
   constructor(url: URL, opts: HttpOptions = {}) {
-    // TODO get the asserts working from @metamask/utils
-    // assertStruct(url.toString(), LocalSnapIdStruct, 'Invalid Snap Id');
-    // // TODO(ritave): Write deepMerge() which merges fetchOptions.
-    // assert(
-    //   opts.fetchOptions === undefined,
-    //   'Currently adding fetch options to local: is unsupported.',
-    // );
+    assertStruct(url.toString(), LocalSnapIdStruct, 'Invalid Snap Id');
+    // TODO(ritave): Write deepMerge() which merges fetchOptions.
+    assert(
+      opts.fetchOptions === undefined,
+      'Currently adding fetch options to local: is unsupported.',
+    );
 
     this.#http = new HttpLocation(
       new URL(url.toString().slice(SnapIdPrefixes.local.length)),
@@ -50,8 +50,7 @@ export class LocalLocation implements SnapLocation {
 function convertCanonical<Result>(
   vfile: VirtualFile<Result>,
 ): VirtualFile<Result> {
-  //TODO get the asserts working from @metamask/utils
-  //   assert(vfile.data.canonicalPath !== undefined);
+  assert(vfile.data.canonicalPath !== undefined);
   vfile.data.canonicalPath = `local:${vfile.data.canonicalPath}`;
   return vfile;
 }

app/core/Snaps/location/location.ts

@@ -1,20 +1,8 @@
-import { SemVerRange, SnapManifest, VirtualFile } from '@metamask/snaps-utils';
+import { SnapManifest, VirtualFile } from '@metamask/snaps-utils';
 import { LocalLocation } from './local';
+import { NpmLocation, NpmOptions } from './npm';
 
-export interface NpmOptions {
-  /**
-   * @default DEFAULT_REQUESTED_SNAP_VERSION
-   */
-  versionRange?: SemVerRange;
-  /**
-   * Whether to allow custom NPM registries outside of {@link DEFAULT_NPM_REGISTRY}.
-   *
-   * @default false
-   */
-  allowCustomRegistries?: boolean;
-}
-
-type DetectSnapLocationOptions = NpmOptions & {
+export type DetectSnapLocationOptions = NpmOptions & {
   /**
    * The function used to fetch data.
    *
@@ -48,6 +36,7 @@ export interface SnapLocation {
  * @param opts - NPM options and feature flags.
  * @returns SnapLocation based on url.
  */
+
 export function detectSnapLocation(
   location: string | URL,
   opts?: DetectSnapLocationOptions,
@@ -56,6 +45,8 @@ export function detectSnapLocation(
   switch (root.protocol) {
     case 'local:':
       return new LocalLocation(root, opts);
+    case 'npm:':
+      return new NpmLocation(root, opts);
     default:
       throw new TypeError(
         `Unrecognized "${root.protocol}" snap location protocol.`,