HTTP Client

Fano Framework provides optional thin wrappers of HTTP clients such as curl and TFPHttpClient class that come with Free Pascal.

HTTP client interfaces

Fano Framework wraps http client and segregate it based on HTTP method. List below shows all HTTP interfaces. These segregated interfaces are provided so developer have more control of what HTTP method is allowed to be executed in code.

IHttpGetClient

Send HTTP GET request. It has one method get() that accept url of target and optional data parameter which contains any data associated with this request.

function get(
    const url : string;
    const data : ISerializeable = nil
) : IResponseStream;

This method returns response from web server as stream.

var http : IHttpGetClient;
    response : IResponseStream;
    resStr : string;
...
response := http.get('http://api.examples.com');
resStr := response.read();

IHttpPostClient

Similar to IHttpGetClient but for HTTP POST request. It has one method post() with same parameters and same return value as get() method above.

var http : IHttpPostClient;
    postData : ISerializeable;
    response : IResponseStream;
    resStr : string;
...
response := http.post('http://api.examples.com', postData);
resStr := response.read();

IHttpPutClient

Similar to IHttpPostClient but for HTTP PUT request.

var http : IHttpPutClient;
    putData : ISerializeable;
    response : IResponseStream;
    resStr : string;
...
response := http.put('http://api.examples.com', putData);
resStr := response.read();

IHttpDeleteClient

Similar to IHttpPostClient but for HTTP DELETE request.

var http : IHttpDeleteClient;
    deleteData : ISerializeable;
    response : IResponseStream;
    resStr : string;
...
response := http.delete('http://api.examples.com', deleteData);
resStr := response.read();

IHttpPatchClient

Similar to IHttpPostClient but for HTTP PATCH request.

var http : IHttpPatchClient;
    patchData : ISerializeable;
    response : IResponseStream;
    resStr : string;
...
response := http.patch('http://api.examples.com', patchData);
resStr := response.read();

IHttpOptionsClient

Similar to IHttpOptionsClient but for HTTP OPTIONS request.

var http : IHttpOptionsClient;
    optData : ISerializeable;
    response : IResponseStream;
    resStr : string;
...
response := http.options('http://api.examples.com', optData);
resStr := response.read();

IHttpHeadClient

Similar to IHttpGetClient but for HTTP HEAD request.

var http : IHttpHeadClient;
    response : IResponseStream;
    resStr : string;
...
response := http.head('http://api.examples.com');
resStr := response.read();

IHttpClientHeaders

This is interface for any class having capability to set HTTP request headers. It contains two methods add() and apply() to add headers and apply headers respectively. Both method returns current instance.

function add(const aheader : string; const avalue : string) : IHttpClientHeaders;

function apply() : IHttpClientHeaders;

For example

var headers : IHttpClientHeaders;
...
headers.add('Content-Type', 'application/json');
headers.add('Content-Length', 120);
headers.apply();

Initialize data for request

You can use any instance of objects so long it implements ISerializeable interface. For example,

var data : IModelParams;
    http : IHttpPostClient;
    headers : IHttpClientHeaders;
...
data := TModelParams.create();
data.writeString('firstname', 'John');
data.writeString('lastname', 'Doe');
headers.add('Content-Type', 'application/json');
response := http.post('http://api.examples.com', data);

Http Client implementation

Curl

To use curl based implementation, you need to add conditiona compilation define {$DEFINE LIBCURL} or via command line compiler argument -dLIBCURL and register any THttp*Factory class to dependency container.

var httpGet : IHttpGetClient;
...
container.add('http.get',THttpGetFactory.create());
...
httpGet := container['http.get'] as IHttpGetClient;

TFPHttpClient

To use TFPHttpClient based implementation just register any TFpcHttp*Factory class to dependency container.

var httpGet : IHttpGetClient;
...
container.add('http.get',TFpcHttpGetFactory.create());
...
httpGet := container['http.get'] as IHttpGetClient;

Null

Null class is provided that does nothing. It it provided so developer can disable http client.

To use null based implementation just register TNullHttpClientFactory class to dependency container.

var httpGet : IHttpGetClient;
...
container.add('http.get',TNullHttpClientFactory.create());
...
httpGet := container['http.get'] as IHttpGetClient;

Explore more

Example web application that load data from Elasticsearch. This example use curl to call Elasticsearch API.
Example SCGI web application that load data from Elasticsearch. This example use TFPHttpClient to call Elasticsearch API.

Documentation