api_client.go

/*
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License.  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package helper

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"regexp"
	"strings"
	"time"
	"unicode/utf8"

	"github.com/apache/incubator-devlake/plugins/core"
	"github.com/apache/incubator-devlake/utils"
)

type ApiClientBeforeRequest func(req *http.Request) error
type ApiClientAfterResponse func(res *http.Response) error

var ErrIgnoreAndContinue = errors.New("ignore and continue")

// ApiClient is designed for simple api requests
type ApiClient struct {
	client        *http.Client
	endpoint      string
	headers       map[string]string
	beforeRequest ApiClientBeforeRequest
	afterReponse  ApiClientAfterResponse
	ctx           context.Context
	logger        core.Logger
}

func NewApiClient(
	endpoint string,
	headers map[string]string,
	timeout time.Duration,
	proxy string,
	ctx context.Context,
) (*ApiClient, error) {
	parsedUrl, err := url.Parse(endpoint)
	if err != nil {
		return nil, fmt.Errorf("Invalid URL: %w", err)
	}
	if parsedUrl.Scheme == "" {
		return nil, fmt.Errorf("Invalid schema")
	}
	err = utils.CheckDNS(parsedUrl.Hostname())
	if err != nil {
		return nil, fmt.Errorf("Failed to resolve DNS: %w", err)
	}
	port, err := utils.ResolvePort(parsedUrl.Port(), parsedUrl.Scheme)
	if err != nil {
		return nil, fmt.Errorf("Failed to resolve Port: %w", err)
	}
	err = utils.CheckNetwork(parsedUrl.Hostname(), port, time.Duration(2)*time.Second)
	if err != nil {
		return nil, fmt.Errorf("Failed to connect: %w", err)
	}
	apiClient := &ApiClient{}
	apiClient.Setup(
		endpoint,
		headers,
		timeout,
	)
	if proxy != "" {
		err = apiClient.SetProxy(proxy)
		if err != nil {
			return nil, err
		}
	}
	apiClient.SetContext(ctx)
	return apiClient, nil
}

func (apiClient *ApiClient) Setup(
	endpoint string,
	headers map[string]string,
	timeout time.Duration,

) {
	apiClient.client = &http.Client{Timeout: timeout}
	apiClient.SetEndpoint(endpoint)
	apiClient.SetHeaders(headers)
}

func (apiClient *ApiClient) SetEndpoint(endpoint string) {
	apiClient.endpoint = endpoint
}
func (apiClient *ApiClient) GetEndpoint() string {
	return apiClient.endpoint
}

func (ApiClient *ApiClient) SetTimeout(timeout time.Duration) {
	ApiClient.client.Timeout = timeout
}

func (apiClient *ApiClient) SetHeaders(headers map[string]string) {
	apiClient.headers = headers
}
func (apiClient *ApiClient) GetHeaders() map[string]string {
	return apiClient.headers
}

func (apiClient *ApiClient) SetBeforeFunction(callback ApiClientBeforeRequest) {
	apiClient.beforeRequest = callback
}

func (apiClient *ApiClient) SetAfterFunction(callback ApiClientAfterResponse) {
	apiClient.afterReponse = callback
}

func (apiClient *ApiClient) SetContext(ctx context.Context) {
	apiClient.ctx = ctx
}

func (apiClient *ApiClient) SetProxy(proxyUrl string) error {
	pu, err := url.Parse(proxyUrl)
	if err != nil {
		return err
	}
	if pu.Scheme == "http" || pu.Scheme == "socks5" {
		apiClient.client.Transport = &http.Transport{Proxy: http.ProxyURL(pu)}
	}
	return nil
}

func (apiClient *ApiClient) SetLogger(logger core.Logger) {
	apiClient.logger = logger
}

func (apiClient *ApiClient) logDebug(format string, a ...interface{}) {
	if apiClient.logger != nil {
		apiClient.logger.Debug(format, a...)
	}
}

func (apiClient *ApiClient) logError(format string, a ...interface{}) {
	if apiClient.logger != nil {
		apiClient.logger.Error(format, a...)
	}
}

func (apiClient *ApiClient) Do(
	method string,
	path string,
	query url.Values,
	body interface{},
	headers http.Header,
) (*http.Response, error) {
	uri, err := GetURIStringPointer(apiClient.endpoint, path, query)
	if err != nil {
		return nil, err
	}
	// process body
	var reqBody io.Reader
	if body != nil {
		reqJson, err := json.Marshal(body)
		if err != nil {
			return nil, err
		}
		reqBody = bytes.NewBuffer(reqJson)
	}
	var req *http.Request
	if apiClient.ctx != nil {
		req, err = http.NewRequestWithContext(apiClient.ctx, method, *uri, reqBody)
	} else {
		req, err = http.NewRequest(method, *uri, reqBody)
	}
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/json")

	// populate headers
	if apiClient.headers != nil {
		for name, value := range apiClient.headers {
			req.Header.Set(name, value)
		}
	}
	for name, values := range headers {
		for _, value := range values {
			req.Header.Add(name, value)
		}
	}

	var res *http.Response
	// before send
	if apiClient.beforeRequest != nil {
		err = apiClient.beforeRequest(req)
		if err != nil {
			return nil, err
		}
	}
	apiClient.logDebug("[api-client] %v %v", method, *uri)
	res, err = apiClient.client.Do(req)
	if err != nil {
		apiClient.logError("[api-client] failed to request %s with error:\n%s", req.URL.String(), err.Error())
		return nil, err
	}

	// after recieve
	if apiClient.afterReponse != nil {
		err = apiClient.afterReponse(res)
		if err == ErrIgnoreAndContinue {
			return res, err
		}
		if err != nil {
			res.Body.Close()
			return nil, err
		}
	}

	return res, err
}

func (apiClient *ApiClient) Get(
	path string,
	query url.Values,
	headers http.Header,
) (*http.Response, error) {
	return apiClient.Do(http.MethodGet, path, query, nil, headers)
}

func (apiClient *ApiClient) Post(
	path string,
	query url.Values,
	body interface{},
	headers http.Header,
) (*http.Response, error) {
	return apiClient.Do(http.MethodPost, path, query, body, headers)
}

func UnmarshalResponse(res *http.Response, v interface{}) error {
	defer res.Body.Close()
	resBody, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return fmt.Errorf("%w %s", err, res.Request.URL.String())
	}
	err = json.Unmarshal(resBody, &v)
	if err != nil {
		return fmt.Errorf("%w %s %s", err, res.Request.URL.String(), string(resBody))
	}
	return nil
}

func GetURIStringPointer(baseUrl string, relativePath string, query url.Values) (*string, error) {
	// If the base URL doesn't end with a slash, and has a relative path attached
	// the values will be removed by the Go package, therefore we need to add a missing slash.
	AddMissingSlashToURL(&baseUrl)
	base, err := url.Parse(baseUrl)
	if err != nil {
		return nil, err
	}
	// If the relative path starts with a '/', we need to remove it or the values will be removed by the Go package.
	relativePath = RemoveStartingSlashFromPath(relativePath)
	u, err := url.Parse(relativePath)
	if err != nil {
		return nil, err
	}
	if query != nil {
		queryString := u.Query()
		for key, value := range query {
			queryString.Set(key, strings.Join(value, ""))
		}

		u.RawQuery = queryString.Encode()
	}
	uri := base.ResolveReference(u).String()
	return &uri, nil
}

func AddMissingSlashToURL(baseUrl *string) {
	pattern := `\/$`
	isMatch, _ := regexp.Match(pattern, []byte(*baseUrl))
	if !isMatch {
		*baseUrl += "/"
	}
}

func RemoveStartingSlashFromPath(relativePath string) string {
	pattern := `^\/`
	byteArrayOfPath := []byte(relativePath)
	isMatch, _ := regexp.Match(pattern, byteArrayOfPath)
	if isMatch {
		// Remove the slash.
		// This is basically the trimFirstRune function found: https://stackoverflow.com/questions/48798588/how-do-you-remove-the-first-character-of-a-string/48798712
		_, i := utf8.DecodeRuneInString(relativePath)
		return relativePath[i:]
	}
	return relativePath
}