Merge pull request #837 from bsingr/develop

Insert pagination utilities from beego/wetalk. Refs #835.

+// Copyright 2014 beego Author. All Rights Reserved.
+//
+// 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 pagination
+
+import (
+	"github.com/astaxie/beego/context"
+)
+
+// Instantiates a Paginator and assigns it to context.Input.Data["paginator"].
+func SetPaginator(context *context.Context, per int, nums int64) (paginator *Paginator) {
+	paginator = NewPaginator(context.Request, per, nums)
+	context.Input.Data["paginator"] = paginator
+	return
+}

+/*
+
+The pagination package provides utilities to setup a paginator within the
+context of a http request.
+
+Usage
+
+In your beego.Controller:
+
+ package controllers
+
+ import "github.com/astaxie/beego/utils/pagination"
+
+ type PostsController struct {
+   beego.Controller
+ }
+
+ func (this *PostsController) ListAllPosts() {
+     // sets this.Data["paginator"] with the current offset (from the url query param)
+     postsPerPage := 20
+     paginator := pagination.SetPaginator(this.Ctx, postsPerPage, CountPosts())
+
+     // fetch the next 20 posts
+     this.Data["posts"] = ListPostsByOffsetAndLimit(paginator.Offset(), postsPerPage)
+ }
+
+
+In your view templates:
+
+ {{if .paginator.HasPages}}
+ <ul class="pagination pagination">
+     {{if .paginator.HasPrev}}
+         <li><a href="{{.paginator.PageLinkFirst}}">{{ i18n .Lang "paginator.first_page"}}</a></li>
+         <li><a href="{{.paginator.PageLinkPrev}}">&laquo;</a></li>
+     {{else}}
+         <li class="disabled"><a>{{ i18n .Lang "paginator.first_page"}}</a></li>
+         <li class="disabled"><a>&laquo;</a></li>
+     {{end}}
+     {{range $index, $page := .paginator.Pages}}
+         <li{{if $.paginator.IsActive .}} class="active"{{end}}>
+             <a href="{{$.paginator.PageLink $page}}">{{$page}}</a>
+         </li>
+     {{end}}
+     {{if .paginator.HasNext}}
+         <li><a href="{{.paginator.PageLinkNext}}">&raquo;</a></li>
+         <li><a href="{{.paginator.PageLinkLast}}">{{ i18n .Lang "paginator.last_page"}}</a></li>
+     {{else}}
+         <li class="disabled"><a>&raquo;</a></li>
+         <li class="disabled"><a>{{ i18n .Lang "paginator.last_page"}}</a></li>
+     {{end}}
+ </ul>
+ {{end}}
+
+See also
+
+http://beego.me/docs/mvc/view/page.md
+
+*/
+package pagination

+// Copyright 2014 beego Author. All Rights Reserved.
+//
+// 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 pagination
+
+import (
+	"math"
+	"net/http"
+	"net/url"
+	"strconv"
+)
+
+// Paginator within the state of a http request.
+type Paginator struct {
+	Request     *http.Request
+	PerPageNums int
+	MaxPages    int
+
+	nums      int64
+	pageRange []int
+	pageNums  int
+	page      int
+}
+
+// Returns the total number of pages.
+func (p *Paginator) PageNums() int {
+	if p.pageNums != 0 {
+		return p.pageNums
+	}
+	pageNums := math.Ceil(float64(p.nums) / float64(p.PerPageNums))
+	if p.MaxPages > 0 {
+		pageNums = math.Min(pageNums, float64(p.MaxPages))
+	}
+	p.pageNums = int(pageNums)
+	return p.pageNums
+}
+
+// Returns the total number of items (e.g. from doing SQL count).
+func (p *Paginator) Nums() int64 {
+	return p.nums
+}
+
+// Sets the total number of items.
+func (p *Paginator) SetNums(nums interface{}) {
+	p.nums, _ = ToInt64(nums)
+}
+
+// Returns the current page.
+func (p *Paginator) Page() int {
+	if p.page != 0 {
+		return p.page
+	}
+	if p.Request.Form == nil {
+		p.Request.ParseForm()
+	}
+	p.page, _ = strconv.Atoi(p.Request.Form.Get("p"))
+	if p.page > p.PageNums() {
+		p.page = p.PageNums()
+	}
+	if p.page <= 0 {
+		p.page = 1
+	}
+	return p.page
+}
+
+// Returns a list of all pages.
+//
+// Usage (in a view template):
+//
+//  {{range $index, $page := .paginator.Pages}}
+//    <li{{if $.paginator.IsActive .}} class="active"{{end}}>
+//      <a href="{{$.paginator.PageLink $page}}">{{$page}}</a>
+//    </li>
+//  {{end}}
+func (p *Paginator) Pages() []int {
+	if p.pageRange == nil && p.nums > 0 {
+		var pages []int
+		pageNums := p.PageNums()
+		page := p.Page()
+		switch {
+		case page >= pageNums-4 && pageNums > 9:
+			start := pageNums - 9 + 1
+			pages = make([]int, 9)
+			for i, _ := range pages {
+				pages[i] = start + i
+			}
+		case page >= 5 && pageNums > 9:
+			start := page - 5 + 1
+			pages = make([]int, int(math.Min(9, float64(page+4+1))))
+			for i, _ := range pages {
+				pages[i] = start + i
+			}
+		default:
+			pages = make([]int, int(math.Min(9, float64(pageNums))))
+			for i, _ := range pages {
+				pages[i] = i + 1
+			}
+		}
+		p.pageRange = pages
+	}
+	return p.pageRange
+}
+
+// Returns URL for a given page index.
+func (p *Paginator) PageLink(page int) string {
+	link, _ := url.ParseRequestURI(p.Request.RequestURI)
+	values := link.Query()
+	if page == 1 {
+		values.Del("p")
+	} else {
+		values.Set("p", strconv.Itoa(page))
+	}
+	link.RawQuery = values.Encode()
+	return link.String()
+}
+
+// Returns URL to the previous page.
+func (p *Paginator) PageLinkPrev() (link string) {
+	if p.HasPrev() {
+		link = p.PageLink(p.Page() - 1)
+	}
+	return
+}
+
+// Returns URL to the next page.
+func (p *Paginator) PageLinkNext() (link string) {
+	if p.HasNext() {
+		link = p.PageLink(p.Page() + 1)
+	}
+	return
+}
+
+// Returns URL to the first page.
+func (p *Paginator) PageLinkFirst() (link string) {
+	return p.PageLink(1)
+}
+
+// Returns URL to the last page.
+func (p *Paginator) PageLinkLast() (link string) {
+	return p.PageLink(p.PageNums())
+}
+
+// Returns true if the current page has a predecessor.
+func (p *Paginator) HasPrev() bool {
+	return p.Page() > 1
+}
+
+// Returns true if the current page has a successor.
+func (p *Paginator) HasNext() bool {
+	return p.Page() < p.PageNums()
+}
+
+// Returns true if the given page index points to the current page.
+func (p *Paginator) IsActive(page int) bool {
+	return p.Page() == page
+}
+
+// Returns the current offset.
+func (p *Paginator) Offset() int {
+	return (p.Page() - 1) * p.PerPageNums
+}
+
+// Returns true if there is more than one page.
+func (p *Paginator) HasPages() bool {
+	return p.PageNums() > 1
+}
+
+// Instantiates a paginator struct for the current http request.
+func NewPaginator(req *http.Request, per int, nums interface{}) *Paginator {
+	p := Paginator{}
+	p.Request = req
+	if per <= 0 {
+		per = 10
+	}
+	p.PerPageNums = per
+	p.SetNums(nums)
+	return &p
+}

+// Copyright 2014 beego Author. All Rights Reserved.
+//
+// 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 pagination
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// convert any numeric value to int64
+func ToInt64(value interface{}) (d int64, err error) {
+	val := reflect.ValueOf(value)
+	switch value.(type) {
+	case int, int8, int16, int32, int64:
+		d = val.Int()
+	case uint, uint8, uint16, uint32, uint64:
+		d = int64(val.Uint())
+	default:
+		err = fmt.Errorf("ToInt64 need numeric not `%T`", value)
+	}
+	return
+}