Crate barc

Body Archive container file format, reader and writer.

BARC is a container file format for the storage or one to many HTTP request/response dialog records. A fixed length, ASCII-only record head specifies lengths of a subsequent series of request and response header blocks and bodies which are stored as raw (unencoded) bytes. When not using the internal compression feature, the format is easily human readable. With compression, the barc CLI tool (barc-cli crate) can be used to view records.

See some sample files in source sample/*.barc.

Other features:

• An additional meta-headers block provides more recording details and can also be used to store application-specific values.

• Sequential or random-access reads by record offset (which could be stored in an external index or database).

• Single-writer sessions are guaranteed safe with N concurrent readers (in or out of process).

• Optional per-record gzip or Brotli compression (headers and bodies)

Structs

BarcFile

Reference to a BARC File by Path, supporting up to 1 writer and N readers concurrently.

BarcReader

BARC file handle for read access. Each reader has its own file handle and position.

BarcWriter

BARC file handle for write access.

BrotliCompressStrategy

Strategy for Brotli compression. Will not compress if a minimum length estimate is not reached.

GzipCompressStrategy

Strategy for gzip compression. Will not compress if a minimum length estimate is not reached.

NoCompressStrategy

Strategy of no (aka Plain) compression.

Record

An owned BARC record with public fields.

Enums

BarcError

Error enumeration for all barc module errors. This may be extended in the future, so exhaustive matching is gently discouraged with an unused variant.

Compression

BARC record compression mode.

DialogConvertError

Error enumeration for failures when converting from a Record to a Dialog. This may be extended in the future, so exhaustive matching is gently discouraged with an unused variant.

EncodeWrapper

Wrapper holding a potentially encoding Write reference for the underlying BARC File reference.

RecordType

BARC record type.

Constants

V2_HEAD_SIZE

Fixed record head size including CRLF terminator: 54 Bytes

V2_MAX_HBLOCK

Maximum header (meta, request, response) block size, including any CRLF terminator: 2²⁰ (1 MiB) - 1.

V2_MAX_RECORD

Maximum total record length, excluding the record head: 2⁴⁸ (256 TiB) - 1. Note: this exceeds the file or partition size limits of many file-systems.

V2_MAX_REQ_BODY

Maximum request body size, including any CRLF terminator: 2⁴⁰ (1 TiB) - 1.

Traits

CompressStrategy

Strategies for BARC record compression encoding on write.

MetaRecorded

Access to BARC Record compatible objects by reference, extending Recorded with meta-headers and a record type.

TryFrom

Similar to the TryFrom trait proposed but not yet available in std.

TryInto

Similar to the TryInto trait proposed but not yet available in std. Blanket implemented for all TryFrom.

Functions

hname_meta_method

Meta HeaderName for the HTTP method used in the request, e.g. “GET”, “POST”, etc.

hname_meta_res_decoded

Meta HeaderName for a list of content or transfer encodings decoded for the current response body. The value is in HTTP content-encoding header format, e.g. “chunked, gzip”.

hname_meta_res_status

Meta HeaderName for the response numeric status code, SPACE, and then a standardized reason phrase, e.g. “200 OK”. The later is intended only for human readers.

hname_meta_res_version

Meta HeaderName for the response version, e.g. “HTTP/1.1”, “HTTP/2.0”, etc.

hname_meta_url

Meta HeaderName for the complete URL used in the request.

write_body

Write body to out, with optional CR+LF end padding, and return the length written. This is primarily an implementation detail of BarcWriter, but is made public for its general diagnostic utility.

write_headers

Write header block to out, with optional CR+LF end padding, and return the length written. This is primarily an implementation detail of BarcWriter, but is made public for its general diagnostic utility.