80 lines
2.0 KiB
Go
80 lines
2.0 KiB
Go
package bitcoin
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import (
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"encoding/json"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"time"
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)
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const apiBaseURL = "https://blockstream.info/api/"
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// A client is the structure that will be used to consume the API
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// endpoints. It holds the login credentials, http client/transport,
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// rate limit information, and the login session timer.
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type client struct {
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httpClient *http.Client
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transport *http.Transport
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}
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// Send an HTTP GET request, and return the processed response
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func (c *client) get(endpoint string, out interface{}, query url.Values) error {
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req, err := http.NewRequest("GET", apiBaseURL+endpoint+"?"+query.Encode(), nil)
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if err != nil {
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return fmt.Errorf("failed to create new GET request: %v", err)
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}
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res, err := c.httpClient.Do(req)
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if err != nil {
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return fmt.Errorf("http GET request failed: %v", err)
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}
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err = c.processResponse(res, out)
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if err != nil {
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return fmt.Errorf("failed to process response: %v", err)
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}
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return nil
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}
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// processResponse takes the body of an HTTP response, and either returns
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// the error code, or unmarshalls the JSON response, extracts
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// rate limit info, and places it into the object
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// output parameter. This function closes the response body after reading it.
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func (c *client) processResponse(res *http.Response, out interface{}) error {
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body, err := io.ReadAll(res.Body)
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res.Body.Close()
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if err != nil {
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return fmt.Errorf("failed to read response body: %v", err)
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}
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if res.StatusCode != 200 && res.StatusCode != 201 {
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return fmt.Errorf("unexpected http status code '%d': %v", res.StatusCode, err)
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}
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err = json.Unmarshal(body, out)
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if err != nil {
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return fmt.Errorf("failed to unmarshal response body: %v", err)
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}
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return nil
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}
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// newClient is the factory function for clients
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func newClient() (*client, error) {
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transport := &http.Transport{
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ResponseHeaderTimeout: 5 * time.Second,
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}
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httpClient := &http.Client{
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Transport: transport,
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}
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// Create a new client
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c := &client{
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httpClient: httpClient,
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transport: transport,
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}
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return c, nil
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}
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