111 lines
2.3 KiB
Go
111 lines
2.3 KiB
Go
package middleware
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import (
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"fmt"
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"io/ioutil"
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"log"
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"net/http"
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"plugin"
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"strings"
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)
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// CreateRegistry creates an empty middleware registry
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// - if loadDir is set -> load all available middlewares
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// inside the local ./middleware folder
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func CreateRegistry(loadDir ...string) *MiddlewareRegistry {
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/* (1) Create registry */
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reg := &MiddlewareRegistry{
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Middlewares: make([]MiddleWare, 0),
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}
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/* (2) If no default to use -> empty registry */
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if len(loadDir) < 1 {
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return reg
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}
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/* (3) List types */
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plugins, err := ioutil.ReadDir(loadDir[0])
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if err != nil {
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log.Fatal(err)
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}
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/* (4) Else try to load each given default */
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for _, file := range plugins {
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// ignore non .so files
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if !strings.HasSuffix(file.Name(), ".so") {
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continue
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}
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err := reg.Add(file.Name())
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if err != nil {
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log.Fatalf("Cannot load plugin '%s'", file.Name())
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}
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}
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return reg
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}
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// Add adds a middleware to the registry; it must be a
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// valid and existing plugin name with or without the .so extension
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// it must be located in the relative directory .build/middleware
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func (tr *MiddlewareRegistry) Add(pluginName string) error {
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/* (1) Check plugin name */
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if len(pluginName) < 1 {
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return fmt.Errorf("Plugin name must not be empty")
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}
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/* (2) Check if valid plugin name */
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if strings.ContainsAny(pluginName, "/") {
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return fmt.Errorf("'%s' can only be a name, not a path", pluginName)
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}
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/* (3) Check plugin extension */
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if !strings.HasSuffix(pluginName, ".so") {
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pluginName = fmt.Sprintf("%s.so", pluginName)
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}
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/* (4) Try to load the plugin */
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p, err := plugin.Open(fmt.Sprintf(".build/middleware/%s", pluginName))
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if err != nil {
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return err
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}
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/* (5) Export wanted properties */
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inspect, err := p.Lookup("Inspect")
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if err != nil {
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return fmt.Errorf("Missing method 'Inspect()'; %s", err)
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}
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/* (6) Cast Inspect */
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inspectCast, ok := inspect.(func(http.Request, *Scope))
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if !ok {
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return fmt.Errorf("Inspect() is malformed")
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}
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/* (7) Add type to registry */
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tr.Middlewares = append(tr.Middlewares, MiddleWare{
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Inspect: inspectCast,
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})
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return nil
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}
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// Runs all middlewares (default browse order)
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func (mr MiddlewareRegistry) Run(req http.Request) Scope {
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/* (1) Initialise scope */
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scope := Scope{}
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/* (2) Execute each middleware */
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for _, m := range mr.Middlewares {
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m.Inspect(req, &scope)
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}
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return scope
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}
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