Add General purpose API wrapper util

support/http/httptest/client_expectation.go

@@ -1,6 +1,7 @@
 package httptest
 
 import (
+	"fmt"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -85,6 +86,37 @@ func (ce *ClientExpectation) ReturnStringWithHeader(
 	return ce.Return(httpmock.ResponderFromResponse(&cResp))
 }
 
+// ReturnMultipleResults registers multiple sequential responses for a given client expectation.
+// Useful for testing retries
+func (ce *ClientExpectation) ReturnMultipleResults(responseSets []ResponseData) *ClientExpectation {
+	var allResponses []httpmock.Responder
+	for _, response := range responseSets {
+		resp := http.Response{
+			Status:     strconv.Itoa(response.Status),
+			StatusCode: response.Status,
+			Body:       httpmock.NewRespBodyFromString(response.Body),
+			Header:     response.Header,
+		}
+		allResponses = append(allResponses, httpmock.ResponderFromResponse(&resp))
+	}
+	responseIndex := 0
+	ce.Client.MockTransport.RegisterResponder(
+		ce.Method,
+		ce.URL,
+		func(req *http.Request) (*http.Response, error) {
+			if responseIndex >= len(allResponses) {
+				panic(fmt.Errorf("no responses available"))
+			}
+
+			resp := allResponses[responseIndex]
+			responseIndex++
+			return resp(req)
+		},
+	)
+
+	return ce
+}
+
 // ReturnJSONWithHeader causes this expectation to resolve to a json-based body with the provided
 // status code and response header.  Panics when the provided body cannot be encoded to JSON.
 func (ce *ClientExpectation) ReturnJSONWithHeader(

support/http/httptest/main.go

@@ -67,3 +67,9 @@ func NewServer(t *testing.T, handler http.Handler) *Server {
 		Expect: httpexpect.New(t, server.URL),
 	}
 }
+
+type ResponseData struct {
+	Status int
+	Body   string
+	Header http.Header
+}

utils/apiclient/client.go

@@ -0,0 +1,97 @@
+package apiclient
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/stellar/go/support/log"
+)
+
+const (
+	defaultMaxRetries         = 5
+	defaultInitialBackoffTime = 1 * time.Second
+)
+
+func isRetryableStatusCode(statusCode int) bool {
+	return statusCode == http.StatusTooManyRequests || statusCode == http.StatusServiceUnavailable
+}
+
+func (c *APIClient) GetURL(endpoint string, queryParams url.Values) string {
+	return fmt.Sprintf("%s/%s?%s", c.BaseURL, endpoint, queryParams.Encode())
+}
+
+func (c *APIClient) CallAPI(reqParams RequestParams) (interface{}, error) {
+	if reqParams.QueryParams == nil {
+		reqParams.QueryParams = url.Values{}
+	}
+
+	if reqParams.Headers == nil {
+		reqParams.Headers = map[string]interface{}{}
+	}
+
+	if c.MaxRetries == 0 {
+		c.MaxRetries = defaultMaxRetries
+	}
+
+	if c.InitialBackoffTime == 0 {
+		c.InitialBackoffTime = defaultInitialBackoffTime
+	}
+
+	if reqParams.Endpoint == "" {
+		return nil, fmt.Errorf("Please set endpoint to query")
+	}
+
+	url := c.GetURL(reqParams.Endpoint, reqParams.QueryParams)
+	reqBody, err := CreateRequestBody(reqParams.RequestType, url)
+	if err != nil {
+		return nil, fmt.Errorf("http request creation failed")
+	}
+
+	SetAuthHeaders(reqBody, c.AuthType, c.AuthHeaders)
+	SetHeaders(reqBody, reqParams.Headers)
+	client := c.HTTP
+	if client == nil {
+		client = &http.Client{}
+	}
+
+	var result interface{}
+	retries := 0
+
+	for retries <= c.MaxRetries {
+		resp, err := client.Do(reqBody)
+		if err != nil {
+			return nil, fmt.Errorf("http request failed: %w", err)
+		}
+		defer resp.Body.Close()
+
+		if resp.StatusCode == http.StatusOK {
+			body, err := ioutil.ReadAll(resp.Body)
+			if err != nil {
+				return nil, fmt.Errorf("failed to read response body: %w", err)
+			}
+
+			if err := json.Unmarshal(body, &result); err != nil {
+				return nil, fmt.Errorf("failed to unmarshal JSON: %w", err)
+			}
+
+			return result, nil
+		} else if isRetryableStatusCode(resp.StatusCode) {
+			retries++
+			backoffDuration := c.InitialBackoffTime * time.Duration(1<<retries)
+			if retries <= c.MaxRetries {
+				log.Debugf("Received retryable status %d. Retrying in %v...\n", resp.StatusCode, backoffDuration)
+				time.Sleep(backoffDuration)
+			} else {
+				return nil, fmt.Errorf("maximum retries reached after receiving status %d", resp.StatusCode)
+			}
+		} else {
+			return nil, fmt.Errorf("API request failed with status %d", resp.StatusCode)
+		}
+	}
+
+	return nil, fmt.Errorf("API request failed after %d retries", retries)
+}

utils/apiclient/client_test.go

@@ -0,0 +1,105 @@
+package apiclient
+
+import (
+	"net/http"
+	"net/url"
+	"testing"
+
+	"github.com/stellar/go/support/http/httptest"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetURL(t *testing.T) {
+	c := &APIClient{
+		BaseURL: "https://stellar.org",
+	}
+
+	queryParams := url.Values{}
+	queryParams.Add("type", "forward")
+	queryParams.Add("federation_type", "bank_account")
+	queryParams.Add("swift", "BOPBPHMM")
+	queryParams.Add("acct", "2382376")
+	furl := c.GetURL("federation", queryParams)
+	assert.Equal(t, "https://stellar.org/federation?acct=2382376&federation_type=bank_account&swift=BOPBPHMM&type=forward", furl)
+}
+
+type testCase struct {
+	name          string
+	mockResponses []httptest.ResponseData
+	expected      interface{}
+	expectedError string
+}
+
+func TestCallAPI(t *testing.T) {
+	testCases := []testCase{
+		{
+			name: "status 200 - Success",
+			mockResponses: []httptest.ResponseData{
+				{Status: http.StatusOK, Body: `{"data": "Okay Response"}`, Header: nil},
+			},
+			expected:      map[string]interface{}{"data": "Okay Response"},
+			expectedError: "",
+		},
+		{
+			name: "success with retries - status 429 and 503 then 200",
+			mockResponses: []httptest.ResponseData{
+				{Status: http.StatusTooManyRequests, Body: `{"data": "First Response"}`, Header: nil},
+				{Status: http.StatusServiceUnavailable, Body: `{"data": "Second Response"}`, Header: nil},
+				{Status: http.StatusOK, Body: `{"data": "Third Response"}`, Header: nil},
+				{Status: http.StatusOK, Body: `{"data": "Fourth Response"}`, Header: nil},
+			},
+			expected:      map[string]interface{}{"data": "Third Response"},
+			expectedError: "",
+		},
+		{
+			name: "failure - status 500",
+			mockResponses: []httptest.ResponseData{
+				{Status: http.StatusInternalServerError, Body: `{"error": "Internal Server Error"}`, Header: nil},
+			},
+			expected:      nil,
+			expectedError: "API request failed with status 500",
+		},
+		{
+			name: "failure - status 401",
+			mockResponses: []httptest.ResponseData{
+				{Status: http.StatusUnauthorized, Body: `{"error": "Bad authorization"}`, Header: nil},
+			},
+			expected:      nil,
+			expectedError: "API request failed with status 401",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			hmock := httptest.NewClient()
+			hmock.On("GET", "https://stellar.org/federation?acct=2382376").
+				ReturnMultipleResults(tc.mockResponses)
+
+			c := &APIClient{
+				BaseURL: "https://stellar.org",
+				HTTP:    hmock,
+			}
+
+			queryParams := url.Values{}
+			queryParams.Add("acct", "2382376")
+
+			reqParams := RequestParams{
+				RequestType: "GET",
+				Endpoint:    "federation",
+				QueryParams: queryParams,
+			}
+
+			result, err := c.CallAPI(reqParams)
+
+			if tc.expectedError != "" {
+				assert.EqualError(t, err, tc.expectedError)
+			} else {
+				assert.NoError(t, err)
+			}
+
+			if tc.expected != nil {
+				assert.Equal(t, tc.expected, result)
+			}
+		})
+	}
+}

utils/apiclient/main.go

@@ -0,0 +1,29 @@
+package apiclient
+
+import (
+	"net/http"
+	"net/url"
+	"time"
+)
+
+type HTTP interface {
+	Do(req *http.Request) (resp *http.Response, err error)
+	Get(url string) (resp *http.Response, err error)
+	PostForm(url string, data url.Values) (resp *http.Response, err error)
+}
+
+type APIClient struct {
+	BaseURL            string
+	HTTP               HTTP
+	AuthType           string
+	AuthHeaders        map[string]interface{}
+	MaxRetries         int
+	InitialBackoffTime time.Duration
+}
+
+type RequestParams struct {
+	RequestType string
+	Endpoint    string
+	QueryParams url.Values
+	Headers     map[string]interface{}
+}

utils/apiclient/request.go

@@ -0,0 +1,61 @@
+package apiclient
+
+import (
+	"encoding/base64"
+	"fmt"
+	"net/http"
+
+	"github.com/stellar/go/support/log"
+)
+
+func CreateRequestBody(requestType string, url string) (*http.Request, error) {
+	req, err := http.NewRequest(requestType, url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("http GET request creation failed: %w", err)
+	}
+	return req, nil
+}
+
+func SetHeaders(req *http.Request, args map[string]interface{}) {
+	for key, value := range args {
+		strValue, ok := value.(string)
+		if !ok {
+			log.Debugf("Skipping non-string value for header %s\n", key)
+			continue
+		}
+
+		req.Header.Set(key, strValue)
+	}
+}
+
+func SetAuthHeaders(req *http.Request, authType string, args map[string]interface{}) error {
+	switch authType {
+	case "basic":
+		username, ok := args["username"].(string)
+		if !ok {
+			return fmt.Errorf("missing or invalid username")
+		}
+		password, ok := args["password"].(string)
+		if !ok {
+			return fmt.Errorf("missing or invalid password")
+		}
+
+		authHeader := "Basic " + base64.StdEncoding.EncodeToString([]byte(username+":"+password))
+		SetHeaders(req, map[string]interface{}{
+			"Authorization": authHeader,
+		})
+
+	case "api_key":
+		apiKey, ok := args["api_key"].(string)
+		if !ok {
+			return fmt.Errorf("missing or invalid API key")
+		}
+		SetHeaders(req, map[string]interface{}{
+			"Authorization": apiKey,
+		})
+
+	default:
+		return fmt.Errorf("unsupported auth type: %s", authType)
+	}
+	return nil
+}