Embed resources into templates

webcontroller/forms.go

@@ -0,0 +1,129 @@
+package webcontroller
+
+import (
+	"fmt"
+	"html/template"
+	"net/http"
+)
+
+// Form is a form which can be rendered in HTML and submitted
+type Form struct {
+	// Name of the form. When this form is submitted this name will be in the `form` parameter
+	Name string
+
+	Title       string        // Shown in a large font above the form
+	PreFormHTML template.HTML // Content to be rendered above the form
+
+	Fields []Field
+
+	BackLink    string // Empty for no back link
+	SubmitLabel string // Label for the submit button
+	SubmitRed   bool   // If the submit button should be red or green
+
+	PostFormHTML template.HTML // Content to be rendered below the form
+
+	// Fields to render if the form has been submitted once
+	Submitted      bool            // If the form has been submitted
+	SubmitSuccess  bool            // If the submission was a success
+	SubmitMessages []template.HTML // Messages telling the user the results
+
+	// Used for letting the browser know which user is logged in
+	Username string
+
+	// Actions to perform when the form is rendered
+	Extra ExtraActions
+}
+
+// Field is a single input field in a form
+type Field struct {
+	// Used for reading the data. Entered data is POSTed back to the same URL with this name
+	Name string
+
+	// Is entered in the input field by default. If this is empty when running
+	// Form.ReadInput() it will be set to the value entered by the user
+	DefaultValue string
+
+	// The value entered by the user. Filled in when running Form.ReadInput()
+	EnteredValue string
+
+	// Text next to the input field
+	Label string
+
+	// Text below the input field
+	Description string
+
+	// Separates fields with a horizontal rule
+	Separator bool
+
+	Type FieldType
+
+	// Only used when Type == FieldTypeCaptcha
+	CaptchaSiteKey string
+}
+
+// ExtraActions contains extra actions to performs when rendering the form
+type ExtraActions struct {
+	// Redirects the browser to a different URL with a HTTP 303: See Other
+	// status. This is useful for redirecting the user to a different page if
+	// the form submission was successful
+	RedirectTo string
+
+	// A cookie to install in the browser when the form is rendered. Useful for
+	// setting / destroying user sessions or configurations
+	SetCookie *http.Cookie
+}
+
+// FieldType defines the type a form field has and how it should be rendered
+type FieldType string
+
+// Fields which can be in a form
+const (
+	FieldTypeText            FieldType = "text"
+	FieldTypeTextarea        FieldType = "textarea"
+	FieldTypeNumber          FieldType = "number"
+	FieldTypeUsername        FieldType = "username"
+	FieldTypeEmail           FieldType = "email"
+	FieldTypeCurrentPassword FieldType = "current-password"
+	FieldTypeNewPassword     FieldType = "new-password"
+	FieldTypeCaptcha         FieldType = "captcha"
+)
+
+// ReadInput reads the form of a request and fills in the values for each field.
+// The return value will be true if this form was submitted and false if the
+// form was not submitted
+func (f *Form) ReadInput(r *http.Request) (success bool) {
+	if r.FormValue("form") != f.Name {
+		f.Submitted = false
+		return false
+	}
+	f.Submitted = true
+
+	for i, field := range f.Fields {
+		field.EnteredValue = r.FormValue(field.Name)
+
+		if field.DefaultValue == "" {
+			field.DefaultValue = field.EnteredValue
+		}
+
+		if field.Type == FieldTypeCaptcha && field.EnteredValue == "" {
+			field.EnteredValue = r.FormValue("g-recaptcha-response")
+		}
+
+		f.Fields[i] = field // Update the new values in the array
+	}
+
+	return true
+}
+
+// FieldVal is a utility function for getting the entered value of a field by
+// its name. By using this function you don't have to use nondescriptive array
+// indexes to get the values. It panics if the field name is not found in the
+// form
+func (f *Form) FieldVal(name string) (enteredValue string) {
+	for _, field := range f.Fields {
+		if field.Name == name {
+			return field.EnteredValue
+		}
+	}
+	panic(fmt.Errorf("FieldVal called on unregistered field name '%s'", name))
+}