[Request] Add API for retrieving mapDetails by mapIdList

[ktKongTong]

I'm working on a local playlist management program that may require data synchronization. There can be more than 100 beatmaps in a single folder. If it is possible to add an API that allows batch retrieval of beatmap details by providing a mapIdList.

[Top-Cat]

Do you have or can you calculate the map hashes? If yes, you can already do this in batches of 50 on the map by hash endpoint

[ktKongTong]

Do you have or can you calculate the map hashes? If yes, you can already do this in batches of 50 on the map by hash endpoint

I can't get or calculate the map hash because the maps I'm handling are uncompressed folders, not zip files.🥲

[Top-Cat]

That sounds like you don't know how map hashes work because them being uncompressed makes no difference

[ktKongTong]

oh, sorry. I mistakenly assumed that map hash was calculated for the entire zipfile. I took a look at the relevant code, and it seems that map hashes is calculated based on the content written to 'Info.dat'. Is that correct?

  val info by lazy {
      infoPath.inputStream().use {
          val byteArrayOutputStream = ByteArrayOutputStream()
          it.copyTo(byteArrayOutputStream, sizeLimit = 50 * 1024 * 1024)
          jackson.readValue<MapInfo>(byteArrayOutputStream.toByteArray())
      }
  }

https://github.com/beatmaps-io/beatsaver-main/blob/60e7537843816984b9ba7e4ba3c0cc3e7b2b07cb/src/jvmMain/kotlin/io/beatmaps/controllers/upload.kt#L343-L356

I tried to calculate it in same way but didn't get the same hash.here is the code.

   val jackson: ObjectMapper = jacksonObjectMapper()
       .enable(SerializationFeature.INDENT_OUTPUT)
       .disable(JsonGenerator.Feature.AUTO_CLOSE_TARGET)
       .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
       .setSerializationInclusion(JsonInclude.Include.NON_NULL)
       .registerModule(KotlinTimeModule())
       .registerModule(JavaTimeModule())
       .disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
   val jsonWriter: ObjectWriter = jackson.writer(BSPrettyPrinter())
   val md = MessageDigest.getInstance("SHA1")

   val info = File("src/main/resources/Info.dat").inputStream().use {
       val byteArrayOutputStream = ByteArrayOutputStream()
       it.copyTo(byteArrayOutputStream, sizeLimit = 50 * 1024 * 1024)
       jackson.readValue<MapInfo>(byteArrayOutputStream.toByteArray())
   }
   DigestOutputStream(OutputStream.nullOutputStream(), md).use { dos ->
       jsonWriter.writeValue(dos, info)
   }
  val fx = "%0" + md.digestLength * 2 + "x"
  val digest = String.format(fx, BigInteger(1, md.digest()))
  println(digest)

[Top-Cat]

Not quite, it's a little hard to follow in this repo. SongCore's implementation may be clearer:

https://github.com/Kylemc1413/SongCore/blob/fbb0684f8bca7a8f7bd482cb623e530d185ca78f/source/SongCore/Utilities/Hashing.cs#L137-L162

[ktKongTong]

Not quite, it's a little hard to follow in this repo. SongCore's implementation may be clearer:

https://github.com/Kylemc1413/SongCore/blob/fbb0684f8bca7a8f7bd482cb623e530d185ca78f/source/SongCore/Utilities/Hashing.cs#L137-L162

It's work. thanks!