/
client.go
353 lines (314 loc) · 7.04 KB
/
client.go
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// Package client is a low-level implementation
// of a mailgun REST client.
/*
This package is generally not intended for package consumers.
*/
package client
import (
"bytes"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"log"
"mime/multipart"
"net/http"
"net/url"
"path"
"reflect"
"strings"
)
// DEBUG enables debugging - requests logged, response copied to stderr.
var DEBUG = false
// Pager is implemented by pager types.
type Pager interface {
SetCaller(Caller)
}
func apierr(res *http.Response) error {
if res.StatusCode > 299 {
defer res.Body.Close()
buf := new(bytes.Buffer)
io.CopyN(buf, res.Body, 80)
return Error{
Status: res.Status,
StatusCode: res.StatusCode,
Stringer: buf,
}
}
return nil
}
// Error is an HTTP error from the endpoint.
type Error struct {
Status string
StatusCode int
fmt.Stringer
}
// Err returns *Error if e is
// Error, nil otherwise.
func Err(e error) *Error {
switch t := e.(type) {
case Error:
return &t
case *Error:
return t
}
return nil
}
// Error implements error.
func (e Error) Error() string {
return fmt.Sprintf("(%v) %s", e.StatusCode, e.Status)
}
func postHeader(h http.Header, boundary string) {
h.Set("Content-Type", fmt.Sprintf(`multipart/form-data; boundary=%s`, boundary))
}
// Requester has methods that return Requests.
type Requester struct {
Endpoint string
APIKey string
APIDomain string
*http.Client
}
var _ = Caller(&Requester{})
// New turns a new Requester.
func New(endpoint, apikey, apidomain string) *Requester {
return &Requester{Endpoint: endpoint, APIKey: apikey, APIDomain: apidomain}
}
// Domain returns the API domain.
func (r *Requester) Domain() string {
return r.APIDomain
}
// Key returns the API key.
func (r *Requester) Key() string {
return r.APIKey
}
// HTTPClient returns the *http.Client associated with this Requester.
func (r *Requester) HTTPClient() *http.Client {
if r.Client != nil {
return r.Client
}
return http.DefaultClient
}
// Request is a client request.
type Request struct {
client Caller
e error
endpoint string
method string
header http.Header
query url.Values
form url.Values
payload io.Reader
}
func (r *Request) err(e error) error {
if r.e == nil {
r.e = e
}
return e
}
func (r *Request) done() {
if r.e == nil {
r.e = fmt.Errorf("request: done")
}
}
// Header returns the http.Header for this Request.
func (r *Request) Header() http.Header {
if r.header == nil {
r.header = make(http.Header)
}
return r.header
}
// SetHeader sets a header, returning Request.
func (r *Request) SetHeader(k, v string) *Request {
r.Header().Set(k, v)
return r
}
// AddHeader adds a header, returning Request.
func (r *Request) AddHeader(k, v string) *Request {
r.Header().Add(k, v)
return r
}
// Query returns the url.Values for this Request's query string.
func (r *Request) Query() url.Values {
if r.query == nil {
r.query = make(url.Values)
}
return r.query
}
// SetQuery sets k,v to query string.
func (r *Request) SetQuery(k, v string) *Request {
r.Query().Set(k, v)
return r
}
// AddQuery adds k,v to query string.
func (r *Request) AddQuery(k, v string) *Request {
r.Query().Add(k, v)
return r
}
// Form returns the url.Values for this Request's form data.
func (r *Request) Form() url.Values {
if r.form == nil {
r.form = make(url.Values)
}
return r.form
}
// SetForm sets k,v to form values.
func (r *Request) SetForm(k, v string) *Request {
r.Form().Set(k, v)
return r
}
// AddForm adds k,v to form values.
func (r *Request) AddForm(k, v string) *Request {
r.Form().Add(k, v)
return r
}
// Payload sets the io.Reader for this Request. Precludes
// Form method.
func (r *Request) Payload(reader io.Reader) *Request {
r.payload = reader
return r
}
// Err performs this request, returning any error.
func (r *Request) Err() error {
res, err := r.Do()
if err != nil {
return r.err(err)
}
return res.Body.Close()
}
func (r *Request) setpager(i interface{}) {
v := reflect.ValueOf(i)
switch v.Kind() {
case reflect.Ptr:
v = v.Elem()
default:
return
}
if sc, ok := v.Interface().(Pager); ok {
sc.SetCaller(r.client)
}
}
// Decode decodes the result of performing r to i.
func (r *Request) Decode(i interface{}) error {
res, err := r.Do()
if err != nil {
return r.err(err)
}
defer res.Body.Close()
if err = json.NewDecoder(res.Body).Decode(i); err != nil {
return r.err(err)
}
r.setpager(i)
return nil
}
// Do performs this Request.
func (r *Request) Do() (*http.Response, error) {
defer r.done()
if r.e != nil {
return nil, r.e
}
client := r.client.HTTPClient()
if len(r.query) > 0 {
r.endpoint += fmt.Sprintf(`?%s`, r.query.Encode())
}
if len(r.form) > 0 {
buf := new(bytes.Buffer)
w := multipart.NewWriter(buf)
for k, v := range r.form {
for _, v := range v {
if err := w.WriteField(k, v); err != nil {
return nil, r.err(err)
}
}
}
if err := w.Close(); err != nil {
return nil, r.err(err)
}
if r.header == nil {
r.header = make(http.Header)
}
postHeader(r.header, w.Boundary())
r.payload = buf
}
if DEBUG {
log.Println("method", r.method)
log.Println("endpoint", r.endpoint)
log.Printf("payload: %T", r.payload)
}
req, err := http.NewRequest(r.method, r.endpoint, r.payload)
if err != nil {
return nil, r.err(err)
}
for k, v := range r.header {
req.Header[k] = v
}
req.SetBasicAuth("api", r.client.Key())
res, err := client.Do(req)
if err != nil {
return nil, r.err(err)
}
if err = apierr(res); err != nil {
return nil, r.err(err)
}
if DEBUG {
defer res.Body.Close()
buf := new(bytes.Buffer)
if _, err = io.Copy(buf, res.Body); err != nil {
panic(err)
}
log.Println(buf.String())
res.Body = ioutil.NopCloser(buf)
}
return res, nil
}
func join(uri []string) string {
pth := path.Join(uri...)
if strings.HasPrefix(pth, `https:/`) {
pth = strings.Replace(pth, `https:/`, `https://`, 1)
}
return pth
}
func (r *Requester) request(method string, uri ...string) *Request {
req := new(Request)
if len(uri) == 0 {
req.e = fmt.Errorf("request: uri not supplied")
return req
}
req.method = method
req.client = r
pth := join(uri)
switch {
case strings.HasPrefix(pth, `https:/`):
req.endpoint = pth
case pth[0] == '/':
req.endpoint = r.Endpoint + pth[1:]
default:
req.endpoint = r.Endpoint + path.Join(r.APIDomain, pth)
}
return req
}
// Get returns a GET Request.
func (r *Requester) Get(uri ...string) *Request {
return r.request(http.MethodGet, uri...)
}
// Post returns a POST Request.
func (r *Requester) Post(uri ...string) *Request {
return r.request(http.MethodPost, uri...)
}
// Put returns a PUT Request.
func (r *Requester) Put(uri ...string) *Request {
return r.request(http.MethodPut, uri...)
}
// Delete returns a DELETE Request.
func (r *Requester) Delete(uri ...string) *Request {
return r.request(http.MethodDelete, uri...)
}
// Caller is the interface to a Requester.
type Caller interface {
HTTPClient() *http.Client
Get(uri ...string) *Request
Post(uri ...string) *Request
Put(uri ...string) *Request
Delete(uri ...string) *Request
Domain() string
Key() string
}