move providers into providers subdirectory

providers/staticjsonFinnhub/client.go

@@ -0,0 +1,84 @@
+package staticjsonFinnhub
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+const apiBaseURL = "https://finnhub.io/api/v1/"
+
+// A client is the structure that will be used to consume the API
+// endpoints. It holds the login credentials, http client/transport,
+// rate limit information, and the login session timer.
+type client struct {
+	apiToken   string
+	httpClient *http.Client
+	transport  *http.Transport
+}
+
+// Send an HTTP GET request, and return the processed response
+func (c *client) get(endpoint string, out interface{}, query url.Values) error {
+	req, err := http.NewRequest("GET", apiBaseURL+endpoint+"?"+query.Encode(), nil)
+	if err != nil {
+		return err
+	}
+	req.Header.Add("X-Finnhub-Token", c.apiToken)
+
+	res, err := c.httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("http get request failed: %v", err)
+	}
+
+	err = c.processResponse(res, out)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// processResponse takes the body of an HTTP response, and either returns
+// the error code, or unmarshalls the JSON response, extracts
+// rate limit info, and places it into the object
+// output parameter. This function closes the response body after reading it.
+func (c *client) processResponse(res *http.Response, out interface{}) error {
+	body, err := io.ReadAll(res.Body)
+	res.Body.Close()
+	if err != nil {
+		return err
+	}
+
+	if res.StatusCode != 200 {
+		return fmt.Errorf("got http response status '%d' but expected 200", res.StatusCode)
+	}
+
+	err = json.Unmarshal(body, out)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// newClient is the factory function for clients - takes an API token
+func newClient(apiToken string) (*client, error) {
+	transport := &http.Transport{
+		ResponseHeaderTimeout: 5 * time.Second,
+	}
+
+	httpClient := &http.Client{
+		Transport: transport,
+	}
+
+	// Create a new client
+	c := &client{
+		apiToken:   apiToken,
+		httpClient: httpClient,
+		transport:  transport,
+	}
+
+	return c, nil
+}