Add a method to pick attributes from a context.

context.go

@@ -2,7 +2,11 @@ package authboss
 
 import (
 	"errors"
+	"fmt"
 	"net/http"
+	"strconv"
+	"strings"
+	"time"
 )
 
 // Context provides context for module operations and callbacks. One obvious
@@ -104,3 +108,34 @@ func (c *Context) SaveUser(key string, storer Storer) error {
 
 	return storer.Put(key, c.User)
 }
+
+// Attributes converts the post form values into an attributes map.
+func (c *Context) Attributes() (Attributes, error) {
+	attr := make(Attributes)
+
+	for name, values := range c.postFormValues {
+		if len(values) == 0 {
+			continue
+		}
+
+		val := values[0]
+		switch {
+		case strings.HasSuffix(name, "_int"):
+			integer, err := strconv.Atoi(val)
+			if err != nil {
+				return nil, fmt.Errorf("%q (%q): could not be converted to an integer: %v", name, val, err)
+			}
+			attr[strings.TrimRight(name, "_int")] = integer
+		case strings.HasSuffix(name, "_date"):
+			date, err := time.Parse(time.RFC3339, val)
+			if err != nil {
+				return nil, fmt.Errorf("%q (%q): could not be converted to a datetime: %v", name, val, err)
+			}
+			attr[strings.TrimRight(name, "_date")] = date.UTC()
+		default:
+			attr[name] = val
+		}
+	}
+
+	return attr, nil
+}

context_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"net/http"
 	"testing"
+	"time"
 )
 
 func TestContext_PutGet(t *testing.T) {
@@ -85,3 +86,33 @@ func TestContext_LoadUser(t *testing.T) {
 		}
 	}
 }
+
+func TestContext_Attributes(t *testing.T) {
+	now := time.Now().UTC()
+
+	ctx := NewContext()
+	ctx.postFormValues = map[string][]string{
+		"a":        []string{"a", "1"},
+		"b_int":    []string{"5", "hello"},
+		"wildcard": nil,
+		"c_date":   []string{now.Format(time.RFC3339)},
+	}
+
+	attr, err := ctx.Attributes()
+	if err != nil {
+		t.Error(err)
+	}
+
+	if got := attr["a"].(string); got != "a" {
+		t.Error("a's value is wrong:", got)
+	}
+	if got := attr["b"].(int); got != 5 {
+		t.Error("b's value is wrong:", got)
+	}
+	if got := attr["c"].(time.Time); got.Unix() != now.Unix() {
+		t.Error("c's value is wrong:", now, got)
+	}
+	if _, ok := attr["wildcard"]; ok {
+		t.Error("We don't need totally empty fields.")
+	}
+}