unable to read price_sheet from CMsgStoreGetUserData

[Therepower]

hey,

i try to fetch CSGO in-game store prices via CMsgStoreGetUserData.

message CMsgStoreGetUserData {
	optional fixed32 price_sheet_version = 1;
	optional int32 currency = 2;
}

 

message CMsgStoreGetUserDataResponse {
	optional int32 result = 1;
	optional int32 currency_deprecated = 2;
	optional string country_deprecated = 3;
	optional fixed32 price_sheet_version = 4;
	optional bytes price_sheet = 8;
}

 

When i receive the "CMsgStoreGetUserDataResponse" i can read result, price_sheet_version without problems but "price_sheet" itself is provided as bytes. When i try to read it i get some unreadable text. I also tried to parse it with  binarykvparser which gives  an error "KV type 48 encountered at offset 207"

How could i read the data provided by price_sheet?

thank you in advance

[Dr. McKay]

I have no idea what format price_sheet is encoded in.

[Therepower]

1 hour ago, Dr. McKay said:

I have no idea what format price_sheet is encoded in.

thanks for your response.

any idea how i could find the encoding type? 

this is how it looks like: https://prnt.sc/ytol2e

 

[Dr. McKay]

I don't know. My best guess would be that it's either protobuf or binary KV, but that doesn't look like either. It could possibly be compressed.

[Valvoja]

I'm trying to do the same thing, I'm using python though. For me the price_sheet starts with b"LZMA\", so I'm guessing it's compressed with LZMA but I wasn't able to decompress it

[Dr. McKay]

That sounds like a reasonable assumption. Game content downloads are sometimes compressed with LZMA, so Valve using it somewhere else makes perfect sense.

[Booms]

I can't decode it with lzma.decompress, because it gets: LZMA_FORMAT_ERROR: File format not recognized....

Any idea what should I do?

[skr1pt]

On 1/26/2025 at 10:48 PM, Booms said:

I can't decode it with lzma.decompress, because it gets: LZMA_FORMAT_ERROR: File format not recognized....

Any idea what should I do?

https://github.com/ValveSoftware/source-sdk-2013/blob/0759e2e8e179d5352d81d0d4aaded72c1704b7a9/src/game/client/econ/store/store_panel.cpp#L610

[skr1pt]

const { LZMA } = require('lzma-native');

function decompressValveLZMA(buffer) {
  if (buffer.length < 13) {
    throw new Error("Buffer too short to be Valve LZMA");
  }
  const magic = buffer.readUInt32BE(0); // Big-Endian
  if (magic !== 0x4C5A4D41) { // 'LZMA'
    throw new Error("Not a Valve LZMA container (magic mismatch)");
  }
  const uncompressedLength = buffer.readUInt32LE(4);
  const compressedLength   = buffer.readUInt32LE(8);
  const expectedTotal = 12 + 5 + compressedLength; // header (12) + props(5) + data
  if (buffer.length < expectedTotal) {
    throw new Error(`Buffer too short: expected ${expectedTotal}, have ${buffer.length}`);
  }
  const props = buffer.slice(12, 12 + 5);
  const lzmaData = buffer.slice(12 + 5, 12 + 5 + compressedLength);
  return new Promise((resolve, reject) => {
    const lzma = new LZMA();
    const lzmaHeader = Buffer.alloc(5 + 8);
    props.copy(lzmaHeader, 0); // копируем 5 байт props
    lzmaHeader.writeUInt32LE(uncompressedLength, 5);
    const fullLzmaStream = Buffer.concat([lzmaHeader, lzmaData]);
    lzma.decompress(fullLzmaStream, (result, error) => {
      if (error) {
        reject(error);
      } else {
        resolve(Buffer.from(result));
      }
    });
  });
}

 

Edited February 19 by skr1pt

[benji]

Could you also kindly share how do you parse this buffer into a readable json or text?

[Valdi]

function decompressValveLZMA(buffer) {
  if (buffer.length < 13) {
    throw new Error("Buffer too short to be Valve LZMA");
  }

  const magic = buffer.readUInt32BE(0); // 'LZMA' magic
  if (magic !== 0x4C5A4D41) {
    throw new Error("Not a Valve LZMA container (magic mismatch)");
  }

  const uncompressedLength = buffer.readUInt32LE(4);
  const compressedLength   = buffer.readUInt32LE(8);
  const expectedTotal = 12 + 5 + compressedLength;

  if (buffer.length < expectedTotal) {
    throw new Error(`Buffer too short: expected ${expectedTotal}, have ${buffer.length}`);
  }

  const props = buffer.slice(12, 17); // 5 байт props
  const lzmaData = buffer.slice(17, 17 + compressedLength);

  return new Promise((resolve, reject) => {
    const lzma = new LZMA();

    // Собираем заголовок LZMA: props (5) + uncompressed size (8 байт LE)
    const lzmaHeader = Buffer.alloc(13);
    props.copy(lzmaHeader, 0);
    lzmaHeader.writeBigUInt64LE(BigInt(uncompressedLength), 5);

    const fullLzmaStream = Buffer.concat([lzmaHeader, lzmaData]);

    lzma.decompress(fullLzmaStream, (result, error) => {
      if (error) {
        reject(error);
      } else {
        resolve(result);
      }
    });
  });
}


var BinaryKVParser = require('binarykvparser');

handlers[Language.StoreGetUserDataResponse] = async (body) => {
	let proto = decodeProto(Protos.CMsgStoreGetUserDataResponse, body);

	const result = await decompressValveLZMA(proto.price_sheet);

	const parsed = BinaryKVParser.parse(result);


}

I hope it will save time for someone