forms: introduce convenience MustParse function (#23)

Author: shoenig

forms.go

@@ -23,6 +23,19 @@ var (
 	ErrParseFailure    = errors.New("could not parse value")
 )
 
+// Parse uses the given Schema to parse the HTTP form values in the given HTTP
+// Request. If the values of the form do not match the schema, or required values
+// are missing, a panic is triggered.
+func MustParse(r *http.Request, schema Schema) {
+	if err := r.ParseForm(); err != nil {
+		panic("forms: " + err.Error())
+	}
+
+	if err := ParseValues(r.Form, schema); err != nil {
+		panic("forms: " + err.Error())
+	}
+}
+
 // Parse uses the given Schema to parse the HTTP form values in the given HTTP
 // Request. If the values of the form do not match the schema, or required values
 // are missing, an error is returned.

forms_test.go

@@ -13,6 +13,69 @@ import (
 	"github.com/shoenig/test/must"
 )
 
+func Test_MustParse(t *testing.T) {
+	t.Parallel()
+
+	request, err := http.NewRequestWithContext(
+		t.Context(), http.MethodPost, "/", nil,
+	)
+	must.NoError(t, err)
+
+	request.PostForm = make(url.Values)
+	request.PostForm.Set("one", "1")
+	request.PostForm.Set("two", "2")
+	request.PostForm.Set("three", "3.1")
+	request.PostForm.Set("four", "true")
+
+	var (
+		one   string
+		two   int
+		three float64
+		four  bool
+	)
+
+	MustParse(request, Schema{
+		"one":   String(&one),
+		"two":   Int(&two),
+		"three": Float(&three),
+		"four":  Bool(&four),
+	})
+	must.Eq(t, "1", one)
+	must.Eq(t, 2, two)
+	must.Eq(t, 3.1, three)
+	must.True(t, four)
+}
+
+func Test_MustParse_panic(t *testing.T) {
+	t.Parallel()
+
+	request, err := http.NewRequestWithContext(
+		t.Context(), http.MethodPost, "/", nil,
+	)
+	must.NoError(t, err)
+
+	request.PostForm = make(url.Values)
+	request.PostForm.Set("one", "1")
+	request.PostForm.Set("three", "3.1")
+	request.PostForm.Set("four", "true")
+
+	var (
+		one   string
+		two   int
+		three float64
+		four  bool
+	)
+
+	must.Panic(t, func() {
+		MustParse(request, Schema{
+			"one":   String(&one),
+			"two":   Int(&two),
+			"three": Float(&three),
+			"four":  Bool(&four),
+		})
+	})
+}
+
 func Test_Parse_singles(t *testing.T) {
 	t.Parallel()