Module encode 

Content protocol: protobuf ItemMessage encoding/decoding, mixin construction, deterministic item-id derivation, and CID <-> sha2-256-digest conversion.

On-chain content is a protobuf ItemMessage: an ordered list of MixinPayloadMessage { mixin_id, payload }, each tagged with a 32-bit mixin ID. The semantic type of an item is implied by which mixins are present (a feed/comment type marker, a profile mixin, etc.), so the same encoding serves a decentralized GitHub, a decentralized Wiki, or arbitrary content — only the mixin set differs.

The 32-byte IpfsHash stored on-chain is the sha2-256 digest of an item’s bytes, extracted from an IPFS CIDv0 multihash (0x12 0x20 || digest). This module converts between the CID (Base58, as IPFS returns) and the digest hex (0x-prefixed) that is what actually reaches the chain events.

Structs

BodyTextMixinMessage

Body text.

ContentInput

Input to a publish: everything a caller wants in a new item revision.

DecodedItem

The decoded, field-extracted view of an item (what a read tool returns).

ImageInput

Caller-supplied image reference for a publish.

ImageMixinMessage

An image reference plus its mipmap pyramid (each level a separate IPFS CID).

ImageSpec

Structured image reference carried in an item.

ItemMessage

The top-level content envelope: an ordered list of mixins.

LanguageMixinMessage

BCP-47 language tag.

MipmapLevel

A mipmap level of an image, as uploaded to IPFS (a pre-encoded CID per level).

MipmapLevelMessage

One mipmap level of an ImageMixinMessage.

MixinPayloadMessage

A single tagged mixin: a 32-bit type discriminator plus its payload.

PreparedContent

A ContentInput whose image reference has been resolved into a complete ImageSpec — the input encode_item actually encodes. Built via ContentInput::to_prepared (usually through the orchestration layer, which performs the IPFS work for path-based inputs).

ProfileMixinMessage

Account profile mixin: signed account type + free-text location.

ProfileSpec

Structured profile fields.

TitleMixinMessage

Human-readable title.

Enums

AccountType

The account-type taxonomy encoded in a ProfileMixinMessage.

ContentType

Fixed, protocol-level content-type vocabulary. The type is encoded by which mixins an item carries; this enum is the closure over the known marker/profile mixins. Document is the default (title + body + language).

Constants

BODY_TEXT_MIXIN_ID

Body text (markdown/plain).

COMMENT_TYPE_MIXIN_ID

Comment-type marker (empty payload).

DEFAULT_LANGUAGE_TAG

Default BCP-47 language tag applied when the caller omits one.

FEED_TYPE_MIXIN_ID

Feed-type marker (empty payload).

IMAGE_MIXIN_ID

Image (full-res + mipmap levels).

LANGUAGE_MIXIN_ID

BCP-47 language tag.

PROFILE_MIXIN_ID

Profile (account type + location), used alongside title/body/language.

TITLE_MIXIN_ID

Human-readable title.

Functions

bytes_to_cid

Raw 32-byte digest -> IPFS CIDv0 (Base58).

bytes_to_hex

[u8; 32] -> 0x-prefixed hex string.

cid_to_digest_hex

IPFS CIDv0 (Base58 sha2-256) -> 0x-prefixed digest hex.

decode_image_mixin

Decode an ImageMixinMessage payload into an ImageSpec, converting each level’s digest back to a CID for display.

decode_item

Decode ItemMessage bytes into an extracted DecodedItem. Unknown mixins are ignored (forward compatibility); a missing/ill-formed mixin degrades that field to None rather than failing the whole decode.

decode_single_mixin

Extract a single mixin’s payload by ID.

derive_item_id

Derive a deterministic item ID from the publishing account, a caller- supplied nonce, and the fixed namespace:

digest_hex_to_cid

sha2-256 digest hex (0x) -> IPFS CIDv0 (Base58), prefixing the 0x12 0x20 multihash header.

encode_image_mixin

Encode an ImageSpec into the ImageMixinMessage payload bytes.

encode_item

Encode a ContentInput into the protobuf ItemMessage bytes, tagging the right mixin set for the chosen ContentType.

hex_to_bytes

0x-prefixed hex (32 bytes) -> [u8; 32].

infer_content_type

Infer the ContentType of a decoded item from its marker/profile mixins.

short_hex

Abbreviate a long hex string to first10...last8 for display.