gproxy-transform

Convert requests, responses, and streaming events between the OpenAI, Anthropic Claude, and Google Gemini APIs.

gproxy-transform is the transform layer of GPROXY, built on the wire types in gproxy-protocol. It is a pure, synchronous library: no HTTP client, no runtime, no I/O.

Usage

[dependencies]
gproxy-transform = "=2.4.0"

Resolve a pair from the source/target operation keys, then run the bytes-level dispatch:

use gproxy_transform::protocol::{ContentGenerationKind, Operation, OperationKey};
use gproxy_transform::{TransformContext, dispatch, resolve};

let source = OperationKey::content_generation(
    Operation::GenerateContent,
    ContentGenerationKind::OpenAiChatCompletions,
);
let target = OperationKey::content_generation(
    Operation::GenerateContent,
    ContentGenerationKind::ClaudeMessages,
);

// Request direction: inbound OpenAI chat body → upstream Claude messages body.
let pair = resolve(source, target)?;
let ctx = TransformContext::new(source, target).with_request("/v1/chat/completions", None);
let converted = dispatch::request_bytes_detailed(pair, &ctx, inbound_body)?;
let upstream_body = converted.value;
let semantic_losses = converted.diagnostics;

// Response direction uses the REVERSE pair.
let back = resolve(target, source)?;
let back_ctx = TransformContext::new(target, source);
let inbound_body = dispatch::response_bytes(back, &back_ctx, upstream_body)?;

// Streaming is stateful and one input event may yield zero or many outputs.
let mut stream = dispatch::StreamConverter::new(back, back_ctx)?;
let inbound_events = stream.push(upstream_frame_data)?;
let final_events = stream.finish()?;

Design

• Pairwise, no intermediate representation. Every conversion is a direct source → target module. This keeps provider-specific quirks in the one file that owns them instead of leaking into a shared IR.
• Organized by operation, not by provider. generate_content, count_tokens, models, embeddings, images, compact.
• Same-kind traffic never enters this crate. Route it as passthrough.
• extra fields are not preserved. Source extra is dropped; target extra starts empty.
• Streaming is 0..N and stateful. Retain one dispatch::StreamConverter (or stream_adapter::SseTransformer) for the whole response so multi-part frames and tool calls split across frames are preserved.
• The default SSE adapter is strict: malformed/oversized frames and abnormal EOF return errors and do not synthesize a successful terminator. Lenient skipping is an explicit StreamOptions choice.
• request_bytes_detailed, response_bytes_detailed, push_detailed, and finish_detailed return structured non-fatal semantic-loss diagnostics.
• Routing tables, database rules, and logging policy belong to the host; gproxy-transform contains no routing-policy module.

Use dispatch::is_wired to check whether a resolved pair has a bytes-level implementation before routing traffic through it.

Modules

License

Licensed under the MIT License.