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matryermatryer
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initial simple client
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4 files changed

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4 files changed

+366
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lines changed

‎client.go

Lines changed: 141 additions & 0 deletions
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package graphql
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import (
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"bytes"
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"context"
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"encoding/json"
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"fmt"
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"io"
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"mime/multipart"
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"net/http"
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"github.com/pkg/errors"
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"golang.org/x/net/context/ctxhttp"
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)
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// Client accesses a GraphQL API.
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type client struct {
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endpoint string
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httpclient *http.Client
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}
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// Do executes a query request and returns the response.
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func (c *client) Do(ctx context.Context, request *Request, response interface{}) error {
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if err := ctx.Err(); err != nil {
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return err
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}
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var requestBody bytes.Buffer
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writer := multipart.NewWriter(&requestBody)
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if err := writer.WriteField("query", request.q); err != nil {
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return errors.Wrap(err, "write query field")
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}
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if len(request.vars) > 0 {
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variablesField, err := writer.CreateFormField("variables")
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if err != nil {
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return errors.Wrap(err, "create variables field")
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}
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if err := json.NewEncoder(variablesField).Encode(request.vars); err != nil {
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return errors.Wrap(err, "encode variables")
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}
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}
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for i := range request.files {
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filename := fmt.Sprintf("file-%d", i+1)
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if i == 0 {
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// just use "file" for the first one
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filename = "file"
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}
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part, err := writer.CreateFormFile(filename, request.files[i].Name)
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if err != nil {
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return errors.Wrap(err, "create form file")
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}
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if _, err := io.Copy(part, request.files[i].R); err != nil {
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return errors.Wrap(err, "preparing file")
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}
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}
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if err := writer.Close(); err != nil {
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return errors.Wrap(err, "close writer")
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}
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var graphResponse = struct {
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Data interface{}
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Errors []graphErr
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}{
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Data: response,
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}
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req, err := http.NewRequest(http.MethodPost, c.endpoint, &requestBody)
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if err != nil {
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return err
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}
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req.Header.Set("Content-Type", writer.FormDataContentType())
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req.Header.Set("Accept", "application/json")
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res, err := ctxhttp.Do(ctx, c.httpclient, req)
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if err != nil {
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return err
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}
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defer res.Body.Close()
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var buf bytes.Buffer
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if _, err := io.Copy(&buf, res.Body); err != nil {
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return errors.Wrap(err, "reading body")
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}
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if err := json.NewDecoder(&buf).Decode(&graphResponse); err != nil {
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return errors.Wrap(err, "decoding response")
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}
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if len(graphResponse.Errors) > 0 {
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// return first error
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return graphResponse.Errors[0]
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}
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return nil
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}
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type graphErr struct {
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Message string
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}
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func (e graphErr) Error() string {
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return "graphql: " + e.Message
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}
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// Request is a GraphQL request.
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type Request struct {
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q string
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vars map[string]interface{}
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files []file
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}
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// NewRequest makes a new Request with the specified string.
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func NewRequest(q string) *Request {
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req := &Request{
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q: q,
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}
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return req
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}
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// Run executes the query and unmarshals the response into response.
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func (req *Request) Run(ctx context.Context, response interface{}) error {
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client := fromContext(ctx)
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if client == nil {
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return errors.New("inappropriate context")
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}
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return client.Do(ctx, req, response)
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}
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// Var sets a variable.
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func (req *Request) Var(key string, value interface{}) {
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if req.vars == nil {
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req.vars = make(map[string]interface{})
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}
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req.vars[key] = value
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}
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// File sets a file to upload.
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func (req *Request) File(filename string, r io.Reader) {
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req.files = append(req.files, file{
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Name: filename,
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R: r,
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})
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}
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// file represents a file to upload.
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type file struct {
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Name string
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R io.Reader
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}

‎client_test.go

Lines changed: 173 additions & 0 deletions
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package graphql
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import (
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"context"
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"io"
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"io/ioutil"
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"net/http"
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"net/http/httptest"
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"strings"
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"testing"
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"time"
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"github.com/matryer/is"
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)
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func TestDo(t *testing.T) {
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is := is.New(t)
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var calls int
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srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
20+
calls++
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is.Equal(r.Method, http.MethodPost)
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query := r.FormValue("query")
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is.Equal(query, `query {}`)
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io.WriteString(w, `{
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"data": {
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"something": "yes"
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}
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}`)
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}))
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defer srv.Close()
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c := &client{
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endpoint: srv.URL,
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httpclient: &http.Client{
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Timeout: 1 * time.Second,
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},
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}
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ctx := context.Background()
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ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
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defer cancel()
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var responseData map[string]interface{}
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err := c.Do(ctx, &Request{q: "query {}"}, &responseData)
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is.NoErr(err)
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is.Equal(calls, 1) // calls
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is.Equal(responseData["something"], "yes")
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}
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func TestDoErr(t *testing.T) {
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is := is.New(t)
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var calls int
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srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
51+
calls++
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is.Equal(r.Method, http.MethodPost)
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query := r.FormValue("query")
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is.Equal(query, `query {}`)
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io.WriteString(w, `{
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"errors": [{
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"message": "Something went wrong"
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}]
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}`)
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}))
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defer srv.Close()
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c := &client{
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endpoint: srv.URL,
64+
httpclient: &http.Client{
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Timeout: 1 * time.Second,
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},
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}
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ctx := context.Background()
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ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
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defer cancel()
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var responseData map[string]interface{}
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err := c.Do(ctx, &Request{q: "query {}"}, &responseData)
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is.True(err != nil)
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is.Equal(err.Error(), "graphql: Something went wrong")
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}
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77+
func TestDoNoResponse(t *testing.T) {
78+
is := is.New(t)
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var calls int
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srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
81+
calls++
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is.Equal(r.Method, http.MethodPost)
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query := r.FormValue("query")
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is.Equal(query, `query {}`)
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io.WriteString(w, `{
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"data": {
87+
"something": "yes"
88+
}
89+
}`)
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}))
91+
defer srv.Close()
92+
c := &client{
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endpoint: srv.URL,
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httpclient: &http.Client{
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Timeout: 1 * time.Second,
96+
},
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}
98+
ctx := context.Background()
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ctx, cancel := context.WithTimeout(ctx, 1*time.Second)
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defer cancel()
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err := c.Do(ctx, &Request{q: "query {}"}, nil)
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is.NoErr(err)
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is.Equal(calls, 1) // calls
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}
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func TestQuery(t *testing.T) {
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is := is.New(t)
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var calls int
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srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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calls++
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query := r.FormValue("query")
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is.Equal(query, "query {}")
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is.Equal(r.FormValue("variables"), `{"username":"matryer"}`+"\n")
115+
_, err := io.WriteString(w, `{"data":{"value":"some data"}}`)
116+
is.NoErr(err)
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}))
118+
defer srv.Close()
119+
ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
120+
defer cancel()
121+
ctx = NewContext(ctx, srv.URL)
122+
123+
req := NewRequest("query {}")
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req.Var("username", "matryer")
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// check variables
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is.True(req != nil)
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is.Equal(req.vars["username"], "matryer")
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var resp struct {
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Value string
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}
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err := req.Run(ctx, &resp)
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is.NoErr(err)
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is.Equal(calls, 1)
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is.Equal(resp.Value, "some data")
138+
139+
}
140+
141+
func TestFile(t *testing.T) {
142+
is := is.New(t)
143+
144+
var calls int
145+
srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
146+
calls++
147+
file, header, err := r.FormFile("file")
148+
is.NoErr(err)
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defer file.Close()
150+
is.Equal(header.Filename, "filename.txt")
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is.Equal(header.Size, int64(14))
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b, err := ioutil.ReadAll(file)
154+
is.NoErr(err)
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is.Equal(string(b), `This is a file`)
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_, err = io.WriteString(w, `{"data":{"value":"some data"}}`)
158+
is.NoErr(err)
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}))
160+
defer srv.Close()
161+
ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
162+
defer cancel()
163+
ctx = NewContext(ctx, srv.URL)
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165+
f := strings.NewReader(`This is a file`)
166+
167+
req := NewRequest("query {}")
168+
req.File("filename.txt", f)
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170+
err := req.Run(ctx, nil)
171+
is.NoErr(err)
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}

‎context.go

Lines changed: 24 additions & 0 deletions
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package graphql
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3+
import "context"
4+
5+
// contextKey provides unique keys for context values.
6+
type contextKey string
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8+
// clientContextKey is the context value key for the Client.
9+
var clientContextKey = contextKey("graphql client context")
10+
11+
// fromContext gets the client from the specified
12+
// Context.
13+
func fromContext(ctx context.Context) *client {
14+
c, _ := ctx.Value(clientContextKey).(*client)
15+
return c
16+
}
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18+
// NewContext makes a new context.Context that enables requests.
19+
func NewContext(parent context.Context, endpoint string) context.Context {
20+
client := &client{
21+
endpoint: endpoint,
22+
}
23+
return context.WithValue(parent, clientContextKey, client)
24+
}

‎context_test.go

Lines changed: 28 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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1+
package graphql
2+
3+
import (
4+
"context"
5+
"testing"
6+
7+
"github.com/matryer/is"
8+
)
9+
10+
func TestNewContext(t *testing.T) {
11+
is := is.New(t)
12+
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testContextKey := contextKey("something")
14+
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ctx := context.Background()
16+
ctx = context.WithValue(ctx, testContextKey, true)
17+
18+
endpoint := "https://server.com/graphql"
19+
ctx = NewContext(ctx, endpoint)
20+
21+
vclient := fromContext(ctx)
22+
is.Equal(vclient.endpoint, endpoint)
23+
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vclient2 := fromContext(ctx)
25+
is.Equal(vclient, vclient2)
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27+
is.Equal(ctx.Value(testContextKey), true) // normal context stuff should work
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}

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