Handlers

This package contains handlers to manage header and cookie values, and identity validation.

Context values middleware

===================

CheckHeader and CheckCookie handlers forward values coming from a request header or a cookie, to a request context.

The mapping is done using enumeration of possible keys, and their mappings to header, context or cookie keys.

Usage

• Read a header from a request and add its value to the underlying request context:

    // Access token
    handler := handlers.CheckHeader(handlers.UserAccess)

    // Locale
    handler := handlers.CheckHeader(handlers.Locale)

    // CollectionID
    handler := handlers.CheckHeader(handlers.CollectionID)

• Read a cookie and add its value to the output request context:

    // Access token
    handler := handlers.CheckCookie(handlers.UserAccess)

    // Locale
    handler := handlers.CheckCookie(handlers.Locale)

    // CollectionID
    handler := handlers.CheckCookie(handlers.CollectionID)

• Access the context value:

    // Access token
    accessToken := ctx.Value(handlers.UserAccess.Context())

    // Locale
    locale := ctx.Value(handlers.Locale.Context())

    // CollectionID
    collectionID := ctx.Value(handlers.CollectionID.Context())

Identity middleware

===================

Middleware component that authenticates requests against zebedee.

The identity and permissions returned from the identity endpoint are added to the request context.

Getting started

Initialise the identity middleware and add it into the HTTP handler chain using alice:

    router := mux.NewRouter()
    alice := alice.New(handlers.Identity(<zebedeeURL>)).Then(router)
    httpServer := server.New(config.BindAddr, alice)

Wrap authenticated endpoints using the handlers.CheckIdentity(handler) function to check that a request identity exists.

    router.Path("/jobs").Methods("POST").HandlerFunc(handlers.CheckIdentity(api.addJob))

Add required headers to outbound requests to other services

    import "github.com/ONSdigital/dp-net/v3/request"

    request.AddServiceTokenHeader(req, api.AuthToken)
    request.AddUserHeader(req, "UserA")

or, put less portably:

    req.Header.Add("Authorization", api.AuthToken)
    req.Header.Add("User-Identity", "UserA")

But most of this should be done by dp-net/v2/http and dp-api-clients-go/v2/....

Testing

If you need to use the middleware component in unit tests you can call the constructor function that allows injection of the HTTP client

import (
    clientsidentity "github.com/ONSdigital/dp-api-clients-go/v2/identity"
    dphttp "github.com/ONSdigital/dp-net/v3/http"
    dphandlers "github.com/ONSdigital/dp-net/v3/handlers"
)

httpClient := &dphttp.ClienterMock{
    DoFunc: func(ctx context.Context, req *http.Request) (*http.Response, error) {
        return &http.Response{
            StatusCode: http.StatusOK,
        }, nil
    },
}
// set last argument to secretKey if you want to support legacy headers
clientsidentity.NewAPIClient(httpClient, zebedeeURL, "")

identityHandler := dphandlers.IdentityWithHTTPClient(doAuth, httpClient)