# HTTP adapter

HTTP adapter provides an HTTP API for sending messages through the platform.

## Configuration

The service is configured using the environment variables presented in the
following table. Note that any unset variables will be replaced with their
default values.

| Variable                    | Description                                                   | Default               |
| --------------------------- | ------------------------------------------------------------- | --------------------- |
| MF_HTTP_ADAPTER_LOG_LEVEL   | Log level for the HTTP Adapter                                | info                  |
| MF_HTTP_ADAPTER_PORT        | Service HTTP port                                             | 80                    |
| MF_BROKER_URL               | Message broker instance URL                                   | nats://localhost:4222 |
| MF_HTTP_ADAPTER_CLIENT_TLS  | Flag that indicates if TLS should be turned on                | false                 |
| MF_HTTP_ADAPTER_CA_CERTS    | Path to trusted CAs in PEM format                             |                       |
| MF_JAEGER_URL               | Jaeger server URL                                             | localhost:6831        |
| MF_THINGS_AUTH_GRPC_URL     | Things service Auth gRPC URL                                  | localhost:7000        |
| MF_THINGS_AUTH_GRPC_TIMEOUT | Things service Auth gRPC request timeout in seconds           | 1s                    |
| MF_SEND_TELEMETRY           | Send telemetry to mainflux call home server                   | true                  |

## Deployment

The service itself is distributed as Docker container. Check the [`http-adapter`](https://github.com/mainflux/mainflux/blob/master/docker/docker-compose.yml#L245-L262) service section in 
docker-compose to see how service is deployed.

To start the service outside of the container, execute the following shell script:

```bash
# download the latest version of the service
git clone https://github.com/mainflux/mainflux

cd mainflux

# compile the http
make http

# copy binary to bin
make install

# set the environment variables and run the service
MF_BROKER_URL=[Message broker instance URL] \
MF_HTTP_ADAPTER_LOG_LEVEL=[HTTP Adapter Log Level] \
MF_HTTP_ADAPTER_PORT=[Service HTTP port] \
MF_HTTP_ADAPTER_CA_CERTS=[Path to trusted CAs in PEM format] \
MF_JAEGER_URL=[Jaeger server URL] \
MF_THINGS_AUTH_GRPC_URL=[Things service Auth gRPC URL] \
MF_THINGS_AUTH_GRPC_TIMEOUT=[Things service Auth gRPC request timeout in seconds] \
$GOBIN/mainflux-http
```

Setting `MF_HTTP_ADAPTER_CA_CERTS` expects a file in PEM format of trusted CAs. This will enable TLS against the Things gRPC endpoint trusting only those CAs that are provided.

## Usage

HTTP Authorization request header contains the credentials to authenticate a Thing. The authorization header can be a plain Thing key
or a Thing key encoded as a password for Basic Authentication. In case the Basic Authentication schema is used, the username is ignored.
For more information about service capabilities and its usage, please check out
the [API documentation](https://api.mainflux.io/?urls.primaryName=http.yml).

[doc]: https://docs.mainflux.io