handler

Documentation

Overview

Package handler contains metadata struct for http handlers; urls, titles, privileges and navigation menu info. It cannot be part of package handlers, since this would cause cyclical dependencies.

Index

• func SetInfos(arg InfosT)
• func ThisFunc() *runtime.Func
• type Info
  • func (l *Info) HasKey(argKey string) bool
  • func (l *Info) RequiresAdmin() bool
• type InfosT
  • func Infos() *InfosT
  • func (l *InfosT) ByHandlerFunc(argFunc http.Handler) (Info, error)
  • func (l *InfosT) ByKey(argKey string) Info
  • func (l *InfosT) ByKeyTranslated(argKey, langCode string) Info
  • func (l *InfosT) ByRuntimeFunc(argFunc *runtime.Func) Info
  • func (l *InfosT) MakeKeys()
  • func (l *InfosT) URLByKey(argKey string) string
• type Privilege
• type TreeT
  • func Tree(lc string) *TreeT
  • func (tr *TreeT) AppendAfterByKey(key string, summand *Info, asChild ...bool) bool
  • func (tr *TreeT) ByKey(key string) *TreeT
  • func (tr *TreeT) NavHTML(w io.Writer, r *http.Request, isLogin bool, l *lgn.LoginT, lvl int)
  • func (tr *TreeT) SetByKey(key string, repl *Info) bool

Functions

func SetInfos

func SetInfos(arg InfosT)

SetInfos saves arg as package variable infos

func ThisFunc

func ThisFunc() *runtime.Func

ThisFunc returns a runtime func info

Types

type Info

type Info struct {
	//
	Keys    []string `json:"keys,omitempty"` // identifier - does not change as URL or title - dynamically derived from the handlerfunc pointer - if not set, then autogenerated from title
	Urls    []string `json:"urls,omitempty"` // first is idiomatic
	OnClick string   `json:"on_click,omitempty"`
	Methods []string `json:"methods,omitempty"` // GET POST ...

	Title       string `json:"title,omitempty"`
	Description string `json:"description,omitempty"` // Meta stuff

	Handler http.HandlerFunc `json:"-"`

	ShortCut string `json:"short_cut,omitempty"` // accesskey attribute in main navi

	// also determines showing up in navigation
	Allow map[Privilege]bool `json:"-"`

	Active bool `json:"-"` // per menu rendering per request/thread
}

Info and Infos keep all the meta information about routes, such as Title, Description, Url(s), [GET,POST,PUT]. They also contain the related handlerFunc. Last not least, they are injected into the template engine, so that URLs are dynamically fetched via {{ index ( byKey "val-delete" ).Urls 0 }}

func (*Info) HasKey

func (l *Info) HasKey(argKey string) bool

HasKey checks an info for some key. Usage in templates, where 'myKey' is known, to determine from a list of HIs, which one "isActive".

func (*Info) RequiresAdmin

func (l *Info) RequiresAdmin() bool

RequiresAdmin checks if a handler requires admin

type InfosT

type InfosT []Info

InfosT models a collection of all app specific handlers

func Infos

func Infos() *InfosT

Infos returns all handlers

func (*InfosT) ByHandlerFunc

func (l *InfosT) ByHandlerFunc(argFunc http.Handler) (Info, error)

ByHandlerFunc returns the handlerinfo for a handler func from outside the request.

handlerFnc, canonPath := mux.Handler(req)
hi, err := handler.HIs.ByHandlerFunc(handlerFnc)

Returns an error, if no handlerinfo exists.

func (*InfosT) ByKey

func (l *InfosT) ByKey(argKey string) Info

ByKey retrieves a handlerinfo by key

func (*InfosT) ByKeyTranslated

func (l *InfosT) ByKeyTranslated(argKey, langCode string) Info

ByKeyTranslated retrieves a handlerinfo by key and translates the title

func (*InfosT) ByRuntimeFunc

func (l *InfosT) ByRuntimeFunc(argFunc *runtime.Func) Info

ByRuntimeFunc retrieves a handlerinfo from *inside* a request handlerFunc:

handler.Infos().ByRuntimeFunc(util.ThisFunc())

Handler funcs - similar to *this* in javaScript can now be retrieved with

myLink := links.Links.ByRuntimeFunc( util.ThisFunc() )

We use

reflect.ValueOf().Pointer() -

and

runtime.Caller() => program counter address => runtime.FuncForPc(pca).Entry()

to compare the two program counter addresses.

I am amazed that this works. Gives every handler access to *its* info object.

func (*InfosT) MakeKeys

func (l *InfosT) MakeKeys()

MakeKeys generates keys, if none exists yet

func (*InfosT) URLByKey

func (l *InfosT) URLByKey(argKey string) string

URLByKey directly returns canonical URL by key

type Privilege

type Privilege int

Privilege encodes some

const (
	// ReadOnly means no saving operation
	ReadOnly Privilege = iota
	// LoggedOut -> only show if no user is logged in
	LoggedOut
	// LoggedIn requires login
	LoggedIn
	// LoggedInViaJSON - must be logged in - and provider must be JSON
	LoggedInViaJSON
	// Admin has all rights
	Admin
	// Editor can save values
	Editor
	// ForwardCopyAllTabs can perform mass copy operations
	ForwardCopyAllTabs
)

type TreeT

type TreeT struct {
	Node     Info // Info may contain just a title string => not clickable
	Children []TreeT
}

TreeT stores nested handler.Info instances

func Tree

func Tree(lc string) *TreeT

Tree returns an application specific nav tree of handler.Info based on which a navigation can be rendered; we dont use a package variable, since the nav tree may be modified by requests

func (*TreeT) AppendAfterByKey

func (tr *TreeT) AppendAfterByKey(key string, summand *Info, asChild ...bool) bool

AppendAfterByKey recursively appends behind an existing node asChild == false => append as sibling - same level asChild == true => append as child - one level deeper

func (*TreeT) ByKey

func (tr *TreeT) ByKey(key string) *TreeT

ByKey recursively retrieves a node; use ByKey() and SetByKey() to modify the nav tree

func (*TreeT) NavHTML

func (tr *TreeT) NavHTML(w io.Writer, r *http.Request, isLogin bool, l *lgn.LoginT, lvl int)

NavHTML - renders a navigation tree into the HTML base snippet below; it is called from templates via template func {{nav .Req}} being mapped to tpl.fcNav

<nav>

<!-- logo text or image are part of the design; they are set via CSS -->
<div class="logo">
</div>

<!-- burger checkbox - out of sight - still can be tabbed and get focus -->
<input type="checkbox" id="mnu-1st-lvl-toggler" class="mnu-1st-lvl-toggler">

<!-- burger label -->
<label for="mnu-1st-lvl-toggler" class="burger">
    <div class="line1"></div>
    <div class="line2"></div>
    <div class="line3"></div>
</label>

<!-- menu second level-->
<ul class="mnu-2nd-lvl">

    {{ .Content}}

    <li><a href="#">Home</a></li>
    <li><a href="#">Blog</a></li>
    <li><a href="#">Contact</a></li>

    <li class='nde-2nd-lvl'>
        <a href='#' onclick='return false;'>Sys Admin</a>

        <ul class='mnu-3rd-lvl'>
            <li><a href='/login-primitive' class=''>Login app</a></li>
            <li><a href='/login-appengine' class=''>Login appengine</a></li>
            <li><a href='/google-token-signin' class=''>Google token sign-in</a></li>
        </ul>
    </li>
    <li class='nde-2nd-lvl'>
        <a href="#">About</a>

        <ul class='mnu-3rd-lvl'>
            <li><a href='/login-primitive' class=''>More</a></li>
            <li><a href='/login-primitive' class=''>Subitems</a></li>
        </ul>

    </li>

</ul>

</nav>

func (*TreeT) SetByKey

func (tr *TreeT) SetByKey(key string, repl *Info) bool

SetByKey recursively replaces an existing node; use ByKey() and SetByKey() to modify the nav tree