containers_2nested_test.go

package containers_test

import (
	"fmt"
	"net/http"
	"strings"

	ct "github.com/theplant/containers"
)

func ComplicatedHome(r *http.Request) (cs []ct.Container, err error) {
	// Get key parameter in `Page` and pass it to all containers that needed the parameter.
	segs := strings.Split(r.RequestURI, "/")
	productCode := segs[len(segs)-1]

	cs = []ct.Container{
		&Header{},
		&MainContent{
			ProductCode:      productCode,
			ProductBasicInfo: &ProductBasicInfo{productCode},
			ProductImages: &ProductImages{
				ProductCode:      productCode,
				ProductMainImage: ct.ContainerFunc(ProductMainImage),
			},
			ProductDescription: &ProductDescription{productCode},
		},
		&Footer{},
	}
	return
}

/*
### Setup a nested containers tree

Build a tree of containers, by using container struct field and render the children container inside parent container manually.
Note that the struct field name has to be exported, means uppercase. Or it can't benefit `reloading` package.
*/
func ExampleContainer_2nested() {

	http.Handle("/page2", ct.PageHandler(ct.PageFunc(ComplicatedHome), nil))
	//Output:

}

// Container MainContent
type MainContent struct {
	ProductCode        string       // use struct field to get inputs from outside of a container.
	ProductBasicInfo   ct.Container // use struct field to pass in a container that used inside another container.
	ProductImages      ct.Container
	ProductDescription ct.Container
}

func (mc *MainContent) Render(r *http.Request) (html string, err error) {
	var basicInfoHtml, imagesHtml, descriptionHtml string

	// inside the container, call `Render` manually to render inside containers.
	if basicInfoHtml, err = mc.ProductBasicInfo.Render(r); err != nil {
		return
	}

	if imagesHtml, err = mc.ProductImages.Render(r); err != nil {
		return
	}

	if descriptionHtml, err = mc.ProductDescription.Render(r); err != nil {
		return
	}

	html = fmt.Sprintf(`
        <div class="main-content">
            %s
            %s
            %s
        </div>
        `,
		basicInfoHtml,
		imagesHtml,
		descriptionHtml,
	)
	return
}

type ProductBasicInfo struct {
	ProductCode string
}

func (bi *ProductBasicInfo) Render(r *http.Request) (html string, err error) {
	db := getDb()
	p := db.GetProduct(bi.ProductCode)
	html = fmt.Sprintf(`
        <div class="basic-info">
            %s
        </div>
    `,
		p.Name,
	)
	return
}

type ProductImages struct {
	ProductCode      string
	ProductMainImage ct.Container
}

func (pi *ProductImages) Render(r *http.Request) (html string, err error) {
	db := getDb()

	var mainImageHtml string
	if mainImageHtml, err = pi.Render(r); err != nil {
		return
	}

	images := db.GetProductImages(pi.ProductCode)
	html = fmt.Sprintf(`
        <div class="images">
            %s
            %v
        </div>
    `,
		mainImageHtml,
		images,
	)
	return
}

func ProductMainImage(r *http.Request) (html string, err error) {
	html = `<div class="product-main-image>main image</div>`
	return
}

type ProductDescription struct {
	ProductCode string
}

func (pd *ProductDescription) Render(r *http.Request) (html string, err error) {
	db := getDb()
	desc := db.GetProductDescription(pd.ProductCode)
	html = fmt.Sprintf(`
        <div class="description">
            %s
        </div>
    `,
		desc,
	)
	return
}