c-polygonid

This is a wrapper library for several PolygonID Go libraries, designed for use with C/C++ languages. It can also be used in mobile development or other infrastructures facing challenges with Go integration.

An overview of the major functions looks like this:

GoUint8 PLGNAtomicQuerySigV2Inputs(char** jsonResponse, char* jsonRequest, char* cfg, PLGNStatus** status);

GoUint8 is a type alias for signed char, which essentially represents a Go bool. It can be 0 or 1. Generally, the function returns 1 in the event of a successful operation and 0 in the event of failure.

If the status pointer is not NULL, a new PLGNStatus object will be allocated, containing details about errors. This object should be freed with the PLGNStatusFree function to avoid a memory leak.

jsonRequest and jsonResponse are plain JSON objects. Their contents depend on the specific function and should be documented in the polygonid.go file. The examples of requests to different functions can be found in testdata directory.

Configuration

The configuration object is a JSON document with the following structure:

{
  "ipfsNodeUrl": "http://localhost:5001", // IPFS Node URL
  "didMethods": [
    {
      "name": "ethr",           // DID method name
      "blockchain": "ethereum", // Blockchain name
      "network": "mainnet",     // Network name
      "networkFlag": 6,         // Network flag
      "methodByte": "0b010011", // Method byte
      "chainID": "10293"
    }
  ],
  "chainConfigs": {
    "1": { // Chain ID as decimal
      "rpcUrl": "http://localhost:8545", // RPC URL
      "stateContractAddr": "0xEA9aF2088B4a9770fC32A12fD42E61BDD317E655" // State contract address
    },
    "0x10": { // Chain ID in hexadecimal format
      "rpcUrl": "http://localhost:8545",
      "stateContractAddr": "0xEA9aF2088B4a9770fC32A12fD42E61BDD317E655"
    }
  },
  // Directory to cache time-consuming operations.
  // If empty, use the default one in user's HOME directory.
  "cacheDir": "/tmp/polygonid"
}

This object should be passed on each call to the library. It is not memorized or cached.

Errors

In case of an error, the function returns 0, and if the pointer to the PLGNStatus struct is not NULL, a struct object will be allocated and filled with the following structure:

typedef struct _PLGNStatus
{
	PLGNStatusCode status;
	char *error_msg;
} PLGNStatus;

Here, PLGNStatusCode is the status enum that can be seen in the .h file included in the distribution of this library, and error_msg is a string containing a detailed, human-readable error.

This object should be freed with PLGNStatusFree function.

Build on macos M1

make darwin-arm64

Build for iOS device

make ios

The Makefile includes several iOS-specific targets for building the library for iOS devices. Here is the list of all targets and the libraries that will be built:

Target	File	Description
ios-arm64	ios/libpolygonid-ios.a	iOS Device arm64 architecture
ios-simulator-x86_64	ios/libpolygonid-ios-simulator-x86_64	iOS Simulator x86_64 architecture
ios-simulator-arm64	ios/libpolygonid-ios-simulator-arm64	iOS Simulator arm64 architecture
ios-old	ios/libpolygonid.a	a universal binary that includes two architectures: - iOS Device arm64 - iOS Simulator x86_64
ios-simulator	ios/libpolygonid-ios-simulator.a	a universal binary that includes two architectures: - iOS Simulator x86_64 - iOS Simulator arm64
ios		Build everything above

After each build target there will be an ios/libpolygonid.h header file.

Run tests

The library build be built with previous command. And copy it to ios/libpolygonid.a file. For example.

make darwin-arm64
cp ios/libpolygonid-darwin-arm64.a ios/libpolygonid.a

Then you can build and run tests.

mkdir examples/build
cd examples/build
cmake ..
cmake --build .
make test ARGS="--rerun-failed --output-on-failure"

Run example on Darwin M1

brew install cjson
make darwin-arm64
cd examples
clang -L../ios -lpolygonid-darwin-arm64 \
        -framework CoreFoundation \
        -framework Security \
        -framework CoreServices \
        `pkg-config --libs --cflags libcjson` \
        json_functions_tests.c && ./a.out