feat: full http client implementation with reqwest like API interface

[zees-dev]

Description

This pull request introduces significant updates to the Blockless SDK, focusing on improving HTTP client functionality, updating examples, and enhancing documentation.

Additionally introduced json-rpc based host-call; through which the HTTP-v2 client operates.
Going forward this will be the single/primary entrypoint/host-call through which all the modules call host functionality.

HTTP Client Enhancements:

• Added a new HTTP client (HttpClient) with support for advanced features such as query parameters, authentication, multipart file uploads, and custom headers. This replaces the legacy BlocklessHttp implementation. (examples/http_client.rs, examples/http_client.rsR1-R175)

Example Updates:

• Updated examples/coingecko_oracle.rs to use the new HttpClient for making HTTP requests, simplifying the code and improving readability. (examples/coingecko_oracle.rs, [1] [2]
• Added a new example examples/ipfs_api.rs demonstrating the use of the HTTP client for interacting with the IPFS API, including file uploads and repository statistics. (examples/ipfs_api.rs, examples/ipfs_api.rsR1-R298)
• Removed the outdated examples/httpbin.rs and replaced it with examples/http_client.rs, showcasing the new HTTP client capabilities. (examples/httpbin.rs, examples/httpbin.rsL1-L26)

Documentation Updates:

• Revised the README.md to reflect changes in build commands, example file names, and descriptions of updated features. (README.md, [1] [2] [3]

Dependency Updates:

• Added the base64 crate as a new dependency to support encoding and decoding operations. (Cargo.toml, Cargo.tomlR13)

Pre-requisites

• feat: single entrypoint json-rpc based host-call blessnetwork/bls-runtime#176

[Copilot]

Pull Request Overview

This PR replaces the legacy HTTP bindings with a full reqwest-like HTTP client built on the new JSON-RPC host call and also introduces a unified RpcClient. Key changes include:

• Added RpcClient for JSON-RPC 2.0 calls in src/rpc.rs
• Replaced BlocklessHttp FFI with HttpClient, HttpOptions, and RequestBuilder in src/http.rs
• Updated examples and README to use the new client and added the base64 dependency

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/rpc.rs	Added unified JSON-RPC client (RpcClient) with error mapping and tests
src/http.rs	Implemented HttpClient, HttpOptions, and RequestBuilder for HTTP RPC
src/lib.rs	Exposed http and rpc modules publicly
README.md	Updated build commands and example references
Cargo.toml	Added base64 dependency
examples/http_client.rs	New HTTP v2 client demo
examples/ipfs_api.rs	New IPFS API example demonstrating file uploads
examples/rpc.rs	New RPC client usage example
examples/httpbin.rs	Removed outdated HTTP example
examples/coingecko_oracle.rs	Updated to use the new HttpClient

Comments suppressed due to low confidence (4)

src/http.rs:79

• [nitpick] The naming for binary body methods is inconsistent: HttpOptions provides body_binary but RequestBuilder uses body_bytes. Consider unifying the method names to improve consistency, e.g., use body_bytes in both places or rename both to body_binary.

    pub fn body_binary(mut self, data: Vec<u8>) -> Self {

src/http.rs:357

• [nitpick] Creating a new RpcClient for each HTTP request can lead to repeated buffer allocations and reset of the next_id counter. Consider reusing a single RpcClient instance inside HttpClient to reduce allocation overhead and preserve request sequencing.

    fn execute(&self, builder: &RequestBuilder) -> Result<HttpResponse, HttpError> {

src/rpc.rs:146

• There are no tests covering the error mapping in RpcClient::call when rpc_call returns non-zero codes. Consider adding unit tests to simulate each return value and verify it maps to the correct RpcError variant.

        if result != 0 {

src/rpc.rs:90

• [nitpick] The public RpcClient API lacks Rustdoc comments. Adding documentation for RpcClient and its key methods (new, call, ping, echo, version) would improve usability and maintainability.

pub struct RpcClient {