Merge pull request #8 from Holo-Host/2021-02-15-add-base64-charset-check

add holohash base64 character set check and tests

src/index.js

@@ -19,6 +19,8 @@ const HOLO_HASH_HEADER_PREFIX = Buffer.from(new Uint8Array([0x84, 0x29, 0x24]).b
 const HOLO_HASH_ENTRY_PREFIX = Buffer.from(new Uint8Array([0x84, 0x21, 0x24]).buffer);
 const HOLO_HASH_DNA_PREFIX = Buffer.from(new Uint8Array([0x84, 0x2d, 0x24]).buffer);
 
+const HOLO_BASE64_CHAR_SET = /^[A-Za-z0-9\-_]+$/;
+
 const getHoloHashPrefix = holoHashType => {
   let holoHashPrefix;
   switch (holoHashType) {
@@ -46,6 +48,12 @@ function check_length(buf, expectedLength) {
   return buf;
 }
 
+function check_charset(string) {
+  if (! HOLO_BASE64_CHAR_SET.test(string))
+  throw new Error(`String ${string} contains characters from outside of Holo base64 character set. Make sure HoloHash base64 encoded string contains only [A-Za-z0-9\-_]`);
+  return string;
+}
+
 function convert_b64_to_holohash_b64(rawBase64) {
   let holoHashbase64 = '';
   const len = rawBase64.length;
@@ -120,6 +128,7 @@ const Codec = {
       return "u" + convert_b64_to_holohash_b64(rawBase64);
     },
     decode: (base64) => {
+      check_charset(base64);
       const buf = Buffer.from(base64.slice(1), "base64").slice(3, -4);
       check_length(Buffer.from(buf), 32);
       return buf;

tests/test_codec.js

@@ -25,6 +25,17 @@ describe("Codec.AgentId", () => {
   });
 });
 
+it("should encode and decode back agent id", async () => {
+  let string = "uhCAkkeIowX20hXW-9wMyh0tQY5Y73RybHi1BdpKdIdbD26Dl_xwq";
+  let result = Codec.AgentId.encode(Codec.AgentId.decode(string));
+  expect(result).to.equal(string);
+});
+
+it("should throw an error when decoding string with chars outside of Holo base64 set", async () => {
+  let string = "uhCAkkeIowX20hXW+9wMyh0tQY5Y73RybHi1BdpKdIdbD26Dl/xwq";
+  expect(() => Codec.AgentId.decode(string)).to.throw();
+});
+
 describe("Codec.Base36", () => {
   it("should decode agent ID using base36 and then encode agent ID back into base36", async () => {
     const urlAgentId = "wjzlh5yt3uk0mzpcor0i12ol0rrpxdydzggt4b2fvr8yealc";
@@ -94,4 +105,4 @@ describe("Codec.Digest", () => {
 
     expect(Codec.Digest.encode(jsonData)).to.equal(hashString);
   });
-});
+});