From 67285ccc086d97cf395331a1e85e4c719afaf70a Mon Sep 17 00:00:00 2001
From: Derrick Hammer <derrick@derrickhammer.com>
Date: Sun, 31 Jul 2022 00:56:54 -0400
Subject: [PATCH] *add modified downloadSkylink that uses the trust-needed
 endpoint and supports a path on the skylink, but also provides the raw
 response object

---
 src/util.ts | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)

diff --git a/src/util.ts b/src/util.ts
index af6b94c..564052e 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -1,3 +1,15 @@
+import {
+  addContextToErr,
+  b64ToBuf,
+  defaultPortalList,
+  Err,
+  objAsString,
+  progressiveFetch,
+  progressiveFetchResult,
+  validSkylink,
+  verifyDownloadResponse,
+} from "libskynet";
+
 export function isIp(ip: string) {
   return /^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/.test(
     ip
@@ -21,3 +33,82 @@ export const requestProxies = [
   { type: "http", host: "skynetfree.net", port: 80 },
   { type: "http", host: "skynetpro.net", port: 80 },
 ];
+
+export function getTld(hostname: string): string {
+  return hostname.includes(".")
+    ? hostname.split(".")[hostname.split(".").length - 1]
+    : hostname;
+}
+
+export type FileDataType = {
+  err: null;
+  response: Response | null;
+  fileData: Uint8Array;
+};
+
+export function downloadSkylink(
+  skylink: string,
+  path?: string
+): Promise<[data: FileDataType, err: Err]> {
+  return new Promise((resolve) => {
+    // Get the Uint8Array of the input skylink.
+    let [u8Link, errBTB] = b64ToBuf(skylink);
+    if (errBTB !== null) {
+      resolve([{} as any, addContextToErr(errBTB, "unable to decode skylink")]);
+      return;
+    }
+    if (!validSkylink(u8Link)) {
+      resolve([{} as any, "skylink appears to be invalid"]);
+      return;
+    }
+
+    // Prepare the download call.
+    let endpoint = "/" + skylink;
+    if (path) {
+      endpoint += path;
+    }
+    let fileDataPtr: FileDataType = {
+      fileData: new Uint8Array(0),
+      err: null,
+      response: null,
+    };
+    let verifyFunction = function (response: Response): Promise<Err> {
+      return verifyDownloadResponse(response, u8Link, fileDataPtr);
+    };
+
+    // Perform the download call.
+    progressiveFetch(endpoint, null, defaultPortalList, () =>
+      Promise.resolve(null)
+    ).then((result: progressiveFetchResult) => {
+      // Return an error if the call failed.
+      if (result.success !== true) {
+        // Check for a 404.
+        for (let i = 0; i < result.responsesFailed.length; i++) {
+          if (result.responsesFailed[i].status === 404) {
+            resolve([{} as any, "404"]);
+            return;
+          }
+        }
+
+        // Error is not a 404, return the logs as the error.
+        let err = objAsString(result.logs);
+        resolve([
+          {} as any,
+          addContextToErr(err, "unable to complete download"),
+        ]);
+        return;
+      }
+      // Check if the portal is honest but the download is corrupt.
+      if (fileDataPtr.err !== null) {
+        resolve([
+          {} as any,
+          addContextToErr(fileDataPtr.err, "download is corrupt"),
+        ]);
+        return;
+      }
+
+      fileDataPtr.response = result.response;
+      resolve([fileDataPtr, null]);
+    });
+  });
+}