[milo] Refactor all html knowledge out of backends.

milo/common/utils.go

-// Copyright 2015 The LUCI Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package common
-
-import (
-        "fmt"
-        "net/http"
-        "strconv"
-)
-
-// GetLimit extracts the "limit", "numbuilds", or "num_builds" http param from
-// the request, or returns "-1" implying no limit was specified.
-func GetLimit(r *http.Request) (int, error) {
-        sLimit := r.FormValue("limit")
-        if sLimit == "" {
-                sLimit = r.FormValue("numbuilds")
-                if sLimit == "" {
-                        sLimit = r.FormValue("num_builds")
-                        if sLimit == "" {
-                                return -1, nil
-                        }
-                }
-        }
-        limit, err := strconv.Atoi(sLimit)
-        if err != nil {
-                return -1, fmt.Errorf("limit parameter value %q is not a number: %s", sLimit, err)
-        }
-        if limit < 0 {
-                return -1, fmt.Errorf("limit parameter value %q is less than 0", sLimit)
-        }
-        return limit, nil
-}