add support for bitcoin

bitcoin/address.go

@@ -0,0 +1,37 @@
+package bitcoin
+
+import (
+	"fmt"
+	"net/url"
+)
+
+type Address struct {
+	Address    string `json:"address"`
+	ChainStats struct {
+		FundedTxoCount int `json:"funded_txo_count"`
+		FundedTxoSum   int `json:"funded_txo_sum"`
+		SpentTxoCount  int `json:"spent_txo_count"`
+		SpentTxoSum    int `json:"spent_txo_sum"`
+		TxCount        int `json:"tx_count"`
+	} `json:"chain_stats"`
+	MempoolStats struct {
+		FundedTxoCount int `json:"funded_txo_count"`
+		FundedTxoSum   int `json:"funded_txo_sum"`
+		SpentTxoCount  int `json:"spent_txo_count"`
+		SpentTxoSum    int `json:"spent_txo_sum"`
+		TxCount        int `json:"tx_count"`
+	} `json:"mempool_stats"`
+}
+
+// GetAddress returns an Address struct populated with data from blockstream.info
+// for a given BTC address
+func (c *Client) GetAddress(address string) (*Address, error) {
+	addressResponse := &Address{}
+
+	err := c.get(fmt.Sprintf("address/%s", address), addressResponse, url.Values{})
+	if err != nil {
+		return nil, err
+	}
+
+	return addressResponse, nil
+}

bitcoin/client.go

@@ -0,0 +1,81 @@
+package bitcoin
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+const apiBaseURL = "https://blockstream.info/api/"
+
+// 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 {
+	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 fmt.Errorf("failed to create new GET request: %v", err)
+	}
+
+	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 fmt.Errorf("failed to process response: %v", 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 fmt.Errorf("failed to read response body: %v", err)
+	}
+
+	if res.StatusCode != 200 && res.StatusCode != 201 {
+		return fmt.Errorf("unexpected http status code '%d': %v", res.StatusCode, err)
+	}
+
+	err = json.Unmarshal(body, out)
+	if err != nil {
+		return fmt.Errorf("failed to unmarshal response body: %v", err)
+	}
+
+	return nil
+}
+
+// NewClient is the factory function for clients
+func NewClient() (*Client, error) {
+	transport := &http.Transport{
+		ResponseHeaderTimeout: 5 * time.Second,
+	}
+
+	client := &http.Client{
+		Transport: transport,
+	}
+
+	// Create a new client
+	c := &Client{
+		httpClient: client,
+		transport:  transport,
+	}
+
+	return c, nil
+}

bitcoin/fiat.go

@@ -0,0 +1,43 @@
+package bitcoin
+
+import (
+	"fmt"
+	"net/http"
+)
+
+// example: https://api.coinconvert.net/convert/btc/cad?amount=1
+const fiatConvertURL = "https://api.coinconvert.net/convert/btc/cad"
+
+type FiatConversion struct {
+	Status string  `json:"status"`
+	BTC    int     `json:"BTC"`
+	CAD    float64 `json:"CAD"`
+}
+
+// BTC to CAD FIAT conversion - accepts an
+// amount in satoshi's and returns a CAD amount * 1000
+func (c *Client) ConvertBTCToCAD(amount int) (int, error) {
+
+	fiatConversion := &FiatConversion{}
+
+	req, err := http.NewRequest("GET", fiatConvertURL+"?amount=1", nil)
+	if err != nil {
+		return 0, fmt.Errorf("failed to create new GET request: %v", err)
+	}
+
+	res, err := c.httpClient.Do(req)
+	if err != nil {
+		return 0, fmt.Errorf("http GET request failed: %v", err)
+	}
+
+	err = c.processResponse(res, fiatConversion)
+	if err != nil {
+		return 0, fmt.Errorf("failed to process response: %v", err)
+	}
+
+	if fiatConversion.Status != "success" {
+		return 0, fmt.Errorf("fiat conversion status was '%s' but expected 'success'", fiatConversion.Status)
+	}
+
+	return (amount * int(fiatConversion.CAD*1000)) / 100000000, nil // one BTC = one hundred million satoshi's
+}