Add api command

api/client.go

@@ -207,6 +207,45 @@ func (c Client) REST(method string, p string, body io.Reader, data interface{})
 	return nil
 }
 
+// DirectRequest is a low-level interface to making generic API requests
+func (c Client) DirectRequest(method string, p string, params interface{}, headers []string) (*http.Response, error) {
+	url := "https://api.github.com/" + p
+	var body io.Reader
+	var bodyIsJSON bool
+
+	switch pp := params.(type) {
+	case map[string]interface{}:
+		b, err := json.Marshal(pp)
+		if err != nil {
+			return nil, fmt.Errorf("error serializing parameters: %w", err)
+		}
+		body = bytes.NewBuffer(b)
+		bodyIsJSON = true
+	case io.Reader:
+		body = pp
+	default:
+		return nil, fmt.Errorf("unrecognized parameters type: %v", params)
+	}
+
+	req, err := http.NewRequest(method, url, body)
+	if err != nil {
+		return nil, err
+	}
+
+	if bodyIsJSON {
+		req.Header.Set("Content-Type", "application/json; charset=utf-8")
+	}
+	for _, h := range headers {
+		idx := strings.IndexRune(h, ':')
+		if idx == -1 {
+			return nil, fmt.Errorf("header %q requires a value separated by ':'", h)
+		}
+		req.Header.Set(h[0:idx], strings.TrimSpace(h[idx+1:]))
+	}
+
+	return c.http.Do(req)
+}
+
 func handleResponse(resp *http.Response, data interface{}) error {
 	success := resp.StatusCode >= 200 && resp.StatusCode < 300
 

command/api.go

@@ -0,0 +1,171 @@
+package command
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/cli/cli/api"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	RootCmd.AddCommand(makeApiCommand())
+}
+
+type ApiOptions struct {
+	RequestMethod       string
+	RequestMethodPassed bool
+	RequestPath         string
+	MagicFields         []string
+	RawFields           []string
+	RequestHeaders      []string
+	ShowResponseHeaders bool
+}
+
+func makeApiCommand() *cobra.Command {
+	opts := ApiOptions{}
+	cmd := &cobra.Command{
+		Use:   "api <endpoint>",
+		Short: "Make an authenticated GitHub API request",
+		Long: `Makes an authenticated HTTP request to the GitHub API and prints the response.
+
+The <endpoint> argument should either be a path of a GitHub API v3 endpoint, or
+"graphql" to access the GitHub API v4.
+
+The default HTTP request method is "GET" normally and "POST" if any parameters
+were added. Override the method with '--method'.
+
+Pass one or more '--raw-field' values in "<key>=<value>" format to add
+JSON-encoded string parameters to the POST body.
+
+The '--field' flag behaves like '--raw-field' with magic type conversion based
+on the format of the value:
+
+- literal values "true", "false", "null", and integer numbers get converted to
+  appropriate JSON types;
+- if the value starts with "@", the rest of the value is interpreted as a
+  filename to read the value from. Pass "-" to read from standard input.
+`,
+		Args: cobra.ExactArgs(1),
+		RunE: func(c *cobra.Command, args []string) error {
+			opts.RequestPath = args[0]
+			opts.RequestMethodPassed = c.Flags().Changed("method")
+
+			ctx := contextForCommand(c)
+			client, err := apiClientForContext(ctx)
+			if err != nil {
+				return err
+			}
+
+			return apiRun(&opts, client)
+		},
+	}
+
+	cmd.Flags().StringVarP(&opts.RequestMethod, "method", "X", "GET", "The HTTP method for the request")
+	cmd.Flags().StringArrayVarP(&opts.MagicFields, "field", "F", nil, "Add a parameter of inferred type")
+	cmd.Flags().StringArrayVarP(&opts.RawFields, "raw-field", "f", nil, "Add a string parameter")
+	cmd.Flags().StringArrayVarP(&opts.RequestHeaders, "header", "H", nil, "Add an additional HTTP request header")
+	cmd.Flags().BoolVarP(&opts.ShowResponseHeaders, "include", "i", false, "Include HTTP response headers in the output")
+	return cmd
+}
+
+func apiRun(opts *ApiOptions, client *api.Client) error {
+	params := make(map[string]interface{})
+	for _, f := range opts.RawFields {
+		key, value, err := parseField(f)
+		if err != nil {
+			return err
+		}
+		params[key] = value
+	}
+	for _, f := range opts.MagicFields {
+		key, strValue, err := parseField(f)
+		if err != nil {
+			return err
+		}
+		value, err := magicFieldValue(strValue)
+		if err != nil {
+			return fmt.Errorf("error parsing %q value: %w", key, err)
+		}
+		params[key] = value
+	}
+
+	method := opts.RequestMethod
+	if len(params) > 0 && !opts.RequestMethodPassed {
+		method = "POST"
+	}
+
+	resp, err := client.DirectRequest(method, opts.RequestPath, params, opts.RequestHeaders)
+	if err != nil {
+		return err
+	}
+
+	if opts.ShowResponseHeaders {
+		for name, vals := range resp.Header {
+			fmt.Printf("%s: %s\r\n", name, strings.Join(vals, ", "))
+		}
+		fmt.Print("\r\n")
+	}
+
+	if resp.StatusCode == 204 {
+		return nil
+	}
+	defer resp.Body.Close()
+
+	// TODO: make stdout configurable for tests
+	_, err = io.Copy(os.Stdout, resp.Body)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func parseField(f string) (string, string, error) {
+	idx := strings.IndexRune(f, '=')
+	if idx == -1 {
+		return f, "", fmt.Errorf("field %q requires a value separated by an '=' sign", f)
+	}
+	return f[0:idx], f[idx+1:], nil
+}
+
+func magicFieldValue(v string) (interface{}, error) {
+	if strings.HasPrefix(v, "@") {
+		return readUserFile(v[1:])
+	}
+
+	if n, err := strconv.Atoi(v); err != nil {
+		return n, nil
+	}
+
+	switch v {
+	case "true":
+		return true, nil
+	case "false":
+		return false, nil
+	case "null":
+		return nil, nil
+	default:
+		return v, nil
+	}
+}
+
+func readUserFile(fn string) ([]byte, error) {
+	var r io.ReadCloser
+	if fn == "-" {
+		// TODO: make stdin configurable for tests
+		r = os.Stdin
+	} else {
+		var err error
+		r, err = os.Open(fn)
+		if err != nil {
+			return nil, err
+		}
+		defer r.Close()
+	}
+	return ioutil.ReadAll(r)
+}