add layer3domain show API call

This adds the API call to return all fields for a single layer3domain.
This should serve as a nice basis for other parts to be implemented.

All fields are put together into a single json document, merged together
with the other attributes of the table and then returned to the
requester.

layer3domain_attr.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 
 	"dim/query"
@@ -43,3 +44,32 @@ func layer3DomainSetAttr(c *Context, req Request, res *Response) error {
 	}
 	return nil
 }
+
+func layer3DomainGetAttr(c *Context, req Request, res *Response) error {
+	name := ""
+	if err := req.ParseAtLeast(1, &name); err != nil {
+		res.AddMessage(LevelError, "could not parse name: %s", err)
+		return nil
+	}
+	if name == "" {
+		res.AddMessage(LevelError, "empt name was provided")
+		return nil
+	}
+
+	result := json.RawMessage{}
+	selClause := query.FieldsToJSON("l", map[string]string{
+		"name":        "name",
+		"modified_by": "l.modified_by",
+		"modified_at": "l.modified_at",
+		"created_by":  "l.created_by",
+		"created_at":  "l.created_at",
+	})
+	queryStr := fmt.Sprintf(`select %s from layer3domains l where name = $1`, selClause)
+	err := c.tx.QueryRow(queryStr, name).Scan(&result)
+	if err != nil {
+		res.AddMessage(LevelError, "could not return result")
+		return fmt.Errorf("could not get layer3domain '%s': %s - query: %s", name, err, queryStr)
+	}
+	res.Result = result
+	return nil
+}

main.go

@@ -66,6 +66,7 @@ func main() {
 	}
 	s.Register("layer3domain_create", layer3DomainCreate)
 	s.Register("layer3domain_list", layer3DomainList)
+	s.Register("layer3domain_get_attr", layer3DomainGetAttr)
 	s.Register("layer3domain_set_attr", layer3DomainSetAttr)
 	s.Register("ipblock_create", ipblockCreate)
 	s.Register("zone_create", zoneCreate)