Add GetExchangeOrdersRate()

README.md

@@ -88,6 +88,7 @@ If you want to execute the Private API, you need to create a client with the API
 | GET /api/ticker | [GetTicker()](https://pkg.go.dev/github.com/nao1215/coincheck#Client.GetTicker) | Check latest ticker information. |
 | GET /api/trades | [GetTrades()](https://pkg.go.dev/github.com/nao1215/coincheck#Client.GetTrades) | You can get current order transactions. |
 | GET /api/order_books | [GetOrderBooks()](https://pkg.go.dev/github.com/nao1215/coincheck#Client.GetOrderBooks) | Fetch order book information. |
+| GET /api/exchange/orders/rate | [GetExchangeOrdersRate()](https://pkg.go.dev/github.com/nao1215/coincheck#Client.GetExchangeOrdersRate) | To calculate the rate from the order of the exchange. |
 | GET /api/rate/[pair] | [GetRate()](https://pkg.go.dev/github.com/nao1215/coincheck#Client.GetRate) | Get the Standard Rate of Coin. |
 
 ### Private API
@@ -104,6 +105,9 @@ If you want to execute the Private API, you need to create a client with the API
 ## Contribution
 First off, thanks for taking the time to contribute! See [CONTRIBUTING.md](./CONTRIBUTING.md) for more information. Contributions are not only related to development. For example, GitHub Star motivates me to develop! Please feel free to contribute to this project.
 
+## Star History
+
+[![Star History Chart](https://api.star-history.com/svg?repos=nao1215/coincheck&type=Date)](https://star-history.com/#nao1215/coincheck&Date)
 
 ## Contributors ✨
 
@@ -135,3 +139,13 @@ Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/d
 <!-- ALL-CONTRIBUTORS-LIST:END -->
 
 This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!
+
+## Reasons for Creating the coincheck package
+
+I wanted to create a Bot that is reason why. Another reason is that I started creating it without much thought. Foolish. Now, I would rather have a bitFlyer Bot.
+
+I received a bonus and bought cryptocurrency out of curiosity (I bought it secretly from my spouse and have already lost 10,000 yen). I became interested in the mechanism of cryptocurrency itself, as well as in how to trade cryptocurrency automatically using a Bot.
+
+The cryptocurrency exchanges I use are Coincheck and bitFlyer, with the former being the one where I hold the most coins. Given this situation, it was natural for me to consider creating a Bot for Coincheck.
+
+However, the official Coincheck API client (Golang) was quite simplistic. I had no choice but to create my own. At this point, I realized my mistake. There was a lot of information that could not be gleaned from the official documentation.

go.mod

@@ -2,4 +2,7 @@ module github.com/nao1215/coincheck
 
 go 1.20
 
-require github.com/google/go-cmp v0.6.0
+require (
+	github.com/google/go-cmp v0.6.0
+	github.com/shogo82148/pointer v1.3.0
+)

go.sum

@@ -1,2 +1,4 @@
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/shogo82148/pointer v1.3.0 h1:LW5V2jUAjFNjS8e7k/PgFoh3EavOSB/vvN85aGue5+I=
+github.com/shogo82148/pointer v1.3.0/go.mod h1:agZ5JFpavFPXznbWonIvbG78NDfvDTFppe+7o53up5w=

order.go

@@ -8,6 +8,11 @@ import (
 // OrderType represents the order type.
 type OrderType string
 
+// String returns the string representation of the OrderType.
+func (o OrderType) String() string {
+	return string(o)
+}
+
 const (
 	// OrderTypeBuy is the order type of buy.
 	OrderTypeBuy OrderType = "buy"

rate.go

@@ -2,6 +2,8 @@ package coincheck
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"net/http"
 )
 
@@ -41,3 +43,63 @@ func (c *Client) GetRate(ctx context.Context, input GetRateInput) (*GetRateRespo
 	}
 	return &output, nil
 }
+
+// GetExchangeOrdersRateInput represents the input for the GetExchangeOrdersRate function.
+// Either price or amount must be specified as a parameter.
+// When both Price and Amount were specified, a status code of 400 was returned in the response.
+type GetExchangeOrdersRateInput struct {
+	// OrderType is the order type. Order type（"sell" or "buy"）
+	OrderType OrderType
+	// Pair is the pair of the currency. e.g. btc_jpy.
+	// Specify a currency pair to trade. btc_jpy, etc_jpy, lsk_jpy, mona_jpy, plt_jpy, fnct_jpy, dai_jpy, wbtc_jpy, bril_jpy are now available.
+	Pair Pair
+	// Price is the price of the order. e.g. 30000.
+	Price *float64
+	// Amount is the amount of the order. e.g. 0.1.
+	Amount *float64
+}
+
+// GetExchangeOrdersRateResponse represents the output from GetExchangeOrdersRate.
+type GetExchangeOrdersRateResponse struct {
+	// Success is a boolean value that indicates the success of the API call.
+	Success bool `json:"success"`
+	// Rate is the rate of the order.
+	Rate string `json:"rate"`
+	// Price is the price of the order.
+	Price string `json:"price"`
+	// Amount is the amount of the order.
+	Amount string `json:"amount"`
+}
+
+// GetExchangeOrdersRate calculate the rate from the order of the exchange.
+// API: GET /api/exchange/orders/rate
+// Visibility: Public
+func (c *Client) GetExchangeOrdersRate(ctx context.Context, input GetExchangeOrdersRateInput) (*GetExchangeOrdersRateResponse, error) {
+	queryParam := map[string]string{
+		"order_type": input.OrderType.String(),
+		"pair":       input.Pair.String(),
+	}
+	if input.Price == nil && input.Amount == nil {
+		return nil, withPrefixError(errors.New("either price or amount must be specified as a parameter"))
+	}
+	if input.Price != nil {
+		queryParam["price"] = fmt.Sprintf("%f", *input.Price)
+	} else {
+		queryParam["amount"] = fmt.Sprintf("%f", *input.Amount)
+	}
+
+	req, err := c.createRequest(ctx, createRequestInput{
+		method:     http.MethodGet,
+		path:       "/api/exchange/orders/rate",
+		queryParam: queryParam,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	var output GetExchangeOrdersRateResponse
+	if err := c.do(req, &output); err != nil {
+		return nil, err
+	}
+	return &output, nil
+}

rate_test.go

@@ -8,6 +8,7 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/shogo82148/pointer"
 )
 
 func TestClient_GetStandardRate(t *testing.T) {
@@ -100,3 +101,161 @@ func TestClient_GetStandardRate(t *testing.T) {
 		}
 	})
 }
+
+func TestClient_GetExchangeOrdersRate(t *testing.T) {
+	t.Run("GetExchangeOrdersRate returns the exchange orders rate (if input valuer set amount)", func(t *testing.T) {
+		testServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			wantMethod := http.MethodGet
+			if got := r.Method; got != wantMethod {
+				t.Errorf("Method: got %v, want %v", got, wantMethod)
+			}
+
+			wantEndpoint := "/api/exchange/orders/rate"
+			if got := r.URL.Path; got != wantEndpoint {
+				t.Errorf("Endpoint: got %v, want %v", got, wantEndpoint)
+			}
+
+			wantPair := PairBTCJPY
+			if got := r.URL.Query().Get("pair"); got != wantPair.String() {
+				t.Errorf("pair: got %v, want %v", got, wantPair)
+			}
+			wantOrderType := OrderTypeBuy
+			if got := r.URL.Query().Get("order_type"); got != wantOrderType.String() {
+				t.Errorf("order_type: got %v, want %v", got, wantOrderType)
+			}
+			wantAmount := "1.200000"
+			if got := r.URL.Query().Get("amount"); got != wantAmount {
+				t.Errorf("amount: got %v, want %v", got, wantAmount)
+			}
+
+			result := GetExchangeOrdersRateResponse{
+				Success: true,
+				Rate:    "9118315.44305",
+				Price:   "10941978.53166054",
+				Amount:  "1.2",
+			}
+			if err := json.NewEncoder(w).Encode(result); err != nil {
+				t.Fatal(err)
+			}
+		}))
+
+		// Create a new client
+		client, err := NewClient(WithBaseURL(testServer.URL))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Start testing
+		input := GetExchangeOrdersRateInput{
+			OrderType: OrderTypeBuy,
+			Pair:      PairBTCJPY,
+			Amount:    pointer.Float64(1.2),
+		}
+		got, err := client.GetExchangeOrdersRate(context.Background(), input)
+		if err != nil {
+			t.Fatal(err)
+		}
+		want := &GetExchangeOrdersRateResponse{
+			Success: true,
+			Rate:    "9118315.44305",
+			Price:   "10941978.53166054",
+			Amount:  "1.2",
+		}
+		if diff := cmp.Diff(want, got); diff != "" {
+			printDiff(t, diff)
+		}
+	})
+
+	t.Run("GetExchangeOrdersRate returns the exchange orders rate (if input valuer set price)", func(t *testing.T) {
+		testServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			wantMethod := http.MethodGet
+			if got := r.Method; got != wantMethod {
+				t.Errorf("Method: got %v, want %v", got, wantMethod)
+			}
+
+			wantEndpoint := "/api/exchange/orders/rate"
+			if got := r.URL.Path; got != wantEndpoint {
+				t.Errorf("Endpoint: got %v, want %v", got, wantEndpoint)
+			}
+
+			wantPair := PairBTCJPY
+			if got := r.URL.Query().Get("pair"); got != wantPair.String() {
+				t.Errorf("pair: got %v, want %v", got, wantPair)
+			}
+			wantOrderType := OrderTypeBuy
+			if got := r.URL.Query().Get("order_type"); got != wantOrderType.String() {
+				t.Errorf("order_type: got %v, want %v", got, wantOrderType)
+			}
+			wantPrice := "1200000.000000"
+			if got := r.URL.Query().Get("price"); got != wantPrice {
+				t.Errorf("price: got %v, want %v", got, wantPrice)
+			}
+
+			result := GetExchangeOrdersRateResponse{
+				Success: true,
+				Rate:    "9118315.44305",
+				Price:   "1200000",
+				Amount:  "1.1",
+			}
+			if err := json.NewEncoder(w).Encode(result); err != nil {
+				t.Fatal(err)
+			}
+		}))
+
+		// Create a new client
+		client, err := NewClient(WithBaseURL(testServer.URL))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Start testing
+		input := GetExchangeOrdersRateInput{
+			OrderType: OrderTypeBuy,
+			Pair:      PairBTCJPY,
+			Price:     pointer.Float64(1200000),
+		}
+		got, err := client.GetExchangeOrdersRate(context.Background(), input)
+		if err != nil {
+			t.Fatal(err)
+		}
+		want := &GetExchangeOrdersRateResponse{
+			Success: true,
+			Rate:    "9118315.44305",
+			Price:   "1200000",
+			Amount:  "1.1",
+		}
+		if diff := cmp.Diff(want, got); diff != "" {
+			printDiff(t, diff)
+		}
+	})
+
+	t.Run("If the amount and pair are empty, GetExchangeOrdersRate returns an error", func(t *testing.T) {
+		client, err := NewClient()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if _, err = client.GetExchangeOrdersRate(context.Background(), GetExchangeOrdersRateInput{}); err == nil {
+			t.Fatal("expected an error, but got nil")
+		}
+	})
+
+	t.Run("GetExchangeOrdersRate returns an error", func(t *testing.T) {
+		testServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		}))
+
+		client, err := NewClient(WithBaseURL(testServer.URL))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if _, err = client.GetExchangeOrdersRate(context.Background(), GetExchangeOrdersRateInput{
+			OrderType: OrderTypeBuy,
+			Pair:      PairBTCJPY,
+			Amount:    pointer.Float64(1.2),
+		}); err == nil {
+			t.Fatal("expected an error, but got nil")
+		}
+	})
+}