dev@locazia: add blockchain routes, edit resolve content system to cid class, add web2 docs

app/core/content/__init__.py

@@ -0,0 +1 @@
+from app.core.content.content_id import ContentId

app/core/content/content_id.py

@@ -0,0 +1,68 @@
+from app.core._utils.string_binary import string_to_bytes_fixed_size, bytes_to_string
+from base58 import b58encode, b58decode
+from app.core._config import ALLOWED_CONTENT_TYPES
+
+# cid_v1#_ cid_version:int8 accept_type:uint120 content_sha256:uint256 onchain_index:uint128 = CIDv1;
+
+
+class ContentId:
+    def __init__(
+        self,
+        content_hash: bytes = None,  # only SHA256
+        onchain_index: int = None,
+        accept_type: str = 'image/jpeg'
+    ):
+        self.content_hash = content_hash
+        self.onchain_index = onchain_index or -1
+
+        self.accept_type = accept_type
+
+    def serialize_v1(self) -> str:
+        at_bin = string_to_bytes_fixed_size(self.accept_type, 15)
+        assert len(self.content_hash) == 32, "Invalid hash length"
+        if self.onchain_index < 0:
+            oi_bin = b''
+        else:
+            oi_bin = self.onchain_index.to_bytes(16, 'big', signed=False)
+            assert len(oi_bin) == 16, "Invalid onchain_index"
+
+        return b58encode(
+            (1).to_bytes(1, 'big')  # cid version
+            + at_bin
+            + self.content_hash
+            + oi_bin
+        ).decode()
+
+    @classmethod
+    def from_v1(cls, cid: str):
+        cid_bin = b58decode(cid)
+        (
+            cid_version,
+            accept_type,
+            content_sha256,
+            onchain_index
+        ) = (
+            int.from_bytes(cid_bin[0:1], 'big'),
+            bytes_to_string(cid_bin[1:16]),
+            cid_bin[16:48],
+            int.from_bytes(cid_bin[48:], 'big') if len(cid_bin) > 48 else -1
+        )
+        assert cid_version == 1, "Invalid version"
+        content_type = accept_type.split('/')
+        assert '/'.join(content_type[0:2]) in ALLOWED_CONTENT_TYPES, "Invalid accept type"
+        assert len(content_sha256) == 32, "Invalid hash length"
+        return cls(
+            content_hash=content_sha256,
+            onchain_index=onchain_index,
+            accept_type=accept_type
+        )
+
+    @classmethod
+    def deserialize(cls, cid: str):
+        cid_version = int.from_bytes(b58decode(cid)[0:1], 'big')
+        if cid_version == 1:
+            return cls.from_v1(cid)
+        else:
+            raise ValueError("Invalid cid version")
+
+