forked from wgroeneveld/go-jamming
124 lines
3.3 KiB
Go
124 lines
3.3 KiB
Go
package rest
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import (
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"errors"
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"fmt"
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"github.com/hashicorp/go-cleanhttp"
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"github.com/hashicorp/go-retryablehttp"
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"io"
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"net/http"
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"net/url"
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"strings"
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"time"
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)
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type Client interface {
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Get(url string) (*http.Response, error)
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Head(url string) (*http.Response, error)
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Post(url string, contentType string, body string) error
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GetBody(url string) (http.Header, string, error)
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PostForm(url string, formData url.Values) error
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}
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type HttpClient struct {
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}
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const (
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MaxBytes = 5000000 // 5 MiB
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RequestUrl string = "requestUrl"
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)
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var (
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// do not use retryablehttp default impl - inject own logger and retry policies
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jammingHttp = &retryablehttp.Client{
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HTTPClient: cleanhttp.DefaultPooledClient(),
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Logger: &zeroLogWrapper{},
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RetryWaitMin: 1 * time.Second,
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RetryWaitMax: 30 * time.Second,
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RetryMax: 5,
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CheckRetry: retryablehttp.DefaultRetryPolicy,
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Backoff: retryablehttp.DefaultBackoff,
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}
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ResponseAboveLimit = errors.New("response bigger than limit")
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)
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func (client *HttpClient) Head(url string) (*http.Response, error) {
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return jammingHttp.Head(url)
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}
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func (client *HttpClient) PostForm(url string, formData url.Values) error {
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resp, err := jammingHttp.PostForm(url, formData)
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if err != nil {
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return fmt.Errorf("POST Form to %s: %v", url, err)
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}
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if !IsStatusOk(resp) {
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return fmt.Errorf("POST Form to %s: Status code is not OK (%d)", url, resp.StatusCode)
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}
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return nil
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}
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func (client *HttpClient) Post(url string, contenType string, body string) error {
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resp, err := jammingHttp.Post(url, contenType, strings.NewReader(body))
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if err != nil {
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return fmt.Errorf("POST to %s: %v", url, err)
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}
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if !IsStatusOk(resp) {
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return fmt.Errorf("POST to %s: Status code is not OK (%d)", url, resp.StatusCode)
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}
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return nil
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}
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// GetBody issues a retryable GET request and returns the header, body string, and a possible error.
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// It limits response sizes to MaxBytes and returns an error if status not between [200, 299].
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func (client *HttpClient) GetBody(url string) (http.Header, string, error) {
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resp, geterr := client.Get(url)
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if geterr != nil {
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return nil, "", fmt.Errorf("GET from %s: %w", url, geterr)
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}
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if !IsStatusOk(resp) {
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return nil, "", fmt.Errorf("GET from %s: Status code is not OK (%d)", url, resp.StatusCode)
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}
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body, readerr := readUntilMax(resp.Body, MaxBytes)
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defer resp.Body.Close()
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if readerr != nil {
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return nil, "", fmt.Errorf("GET from %s: unable to read body: %w", url, readerr)
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}
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resp.Header.Set(RequestUrl, resp.Request.URL.String())
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return resp.Header, string(body), nil
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}
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func IsStatusOk(resp *http.Response) bool {
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return resp.StatusCode >= 200 && resp.StatusCode <= 299
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}
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func (client *HttpClient) Get(url string) (*http.Response, error) {
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return jammingHttp.Get(url)
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}
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// readUntilMax is a duplicate of io.Read(). It behaves exactly the same.
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// However, it will only read maxBytes bytes, exponentially chunked (as per append).
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// Returns an error if it exceeds the limit.
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func readUntilMax(r io.Reader, maxBytes int) ([]byte, error) {
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b := make([]byte, 0, 512)
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for {
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if len(b) == cap(b) {
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// Add more capacity (let append pick how much).
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b = append(b, 0)[:len(b)]
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}
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n, err := r.Read(b[len(b):cap(b)])
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b = b[:len(b)+n]
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if err != nil {
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if err == io.EOF {
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err = nil
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}
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return b, err
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}
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if len(b) > maxBytes {
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return nil, ResponseAboveLimit
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}
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}
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}
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