middleware func to attach remote ip to context

1 files changed, 215 insertions, 0 deletions

diff --git a/http.go b/http.go
new file mode 100644
index 0000000..52f9923
--- /dev/null
+++ b/http.go
@@ -0,0 +1,215 @@
+package main
+
+import (
+	"context"
+	"crypto/sha256"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/gorilla/mux"
+)
+
+// Attaches a request's IP address to the request's context
+func newCtxUserIP(ctx context.Context, r *http.Request) context.Context {
+	base := strings.Split(r.RemoteAddr, ":")
+	uip := base[0]
+	return context.WithValue(ctx, ctxKey, uip)
+}
+
+// Retrieves a request's IP address from the request's context
+func getIPFromCtx(ctx context.Context) string {
+	uip, ok := ctx.Value(ctxKey).(string)
+	if !ok {
+		log.Printf("Couldn't retrieve IP from request\n")
+	}
+	return uip
+}
+
+// Shim function to modify/pass context value to a handler
+func ipMiddleware(hop http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ctx := newCtxUserIP(r.Context(), r)
+		hop.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+// handles "/"
+func indexHandler(w http.ResponseWriter, r *http.Request) {
+	uip := getIPFromCtx(r.Context())
+	log.Printf("Request from %v :: %v %v\n", uip, r.Method, r.URL)
+
+	// Stat the index template to get the mod time
+	var etag string
+	if indextmpl, err := os.Stat("assets/tmpl/index.html"); err != nil {
+		log.Printf("Couldn't stat index template for ETag ... %v\n", err)
+	} else {
+		etag = fmt.Sprintf("%x", sha256.Sum256([]byte(indextmpl.ModTime().String())))
+	}
+
+	// Take the hex-encoded sha256 sum of the index template's mod time
+	// to send as an ETag. If an error occured when grabbing the file info,
+	// the ETag will be empty.
+	w.Header().Set("ETag", "\""+etag+"\"")
+	w.Header().Set("Content-Type", htmlutf8)
+
+	// Pass the confObj.Instance data to the template,
+	// then send it to the client.
+	err := tmpls.ExecuteTemplate(w, "index.html", confObj.Instance)
+	if err != nil {
+		log.Printf("500: Error writing to HTTP stream: %v, %v %v via %v\n", err, r.Method, r.URL, uip)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+}
+
+// handles "/api"
+func apiBaseHandler(w http.ResponseWriter, r *http.Request) {
+	uip := getIPFromCtx(r.Context())
+	log.Printf("Request from %v :: %v %v\n", uip, r.Method, r.URL)
+
+	timerfc3339, err := time.Now().MarshalText()
+	if err != nil {
+		log.Printf("Couldn't format time as RFC3339: %v\n", err)
+	}
+	etag := fmt.Sprintf("%x", sha256.Sum256(timerfc3339))
+	w.Header().Set("ETag", etag)
+	w.Header().Set("Content-Type", txtutf8)
+	pathdata := []byte("\n\n" + r.URL.Path)
+	timerfc3339 = append(timerfc3339, pathdata...)
+	n, err := w.Write(timerfc3339)
+	if err != nil || n == 0 {
+		log.Printf("500: Error writing to HTTP stream: %v, %v %v via %v\n", err, r.Method, r.URL, uip)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+}
+
+// handles "/api/plain"
+// maybe add json/xml support later
+func apiFormatHandler(w http.ResponseWriter, r *http.Request) {
+	uip := getIPFromCtx(r.Context())
+	log.Printf("Request from %v :: %v %v\n", uip, r.Method, r.URL)
+
+	vars := mux.Vars(r)
+	format := vars["format"]
+
+	w.Header().Set("Content-Type", txtutf8)
+	n, err := w.Write([]byte(format + "\n"))
+	if err != nil || n == 0 {
+		log.Printf("500: Error writing to HTTP stream: %v, %v %v via %v\n", err, r.Method, r.URL, uip)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+}
+
+// handles "/api/plain/(users|mentions|tweets)"
+func apiEndpointHandler(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	format := vars["format"]
+	endpoint := vars["endpoint"]
+
+	uip := getIPFromCtx(r.Context())
+	log.Printf("Request from %v :: %v %v\n", uip, r.Method, r.URL)
+
+	w.Header().Set("Content-Type", htmlutf8)
+	n, err := w.Write([]byte(format + "/" + endpoint))
+	if err != nil || n == 0 {
+		log.Printf("500: Error writing to HTTP stream: %v, %v %v via %v\n", err, r.Method, r.URL, uip)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+
+}
+
+// handles POST for "/api/plain/users"
+func apiEndpointPOSTHandler(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	format := vars["format"]
+	endpoint := vars["endpoint"]
+
+	uip := getIPFromCtx(r.Context())
+	log.Printf("Request from %v :: %v %v\n", uip, r.Method, r.URL)
+
+	w.Header().Set("Content-Type", htmlutf8)
+	n, err := w.Write([]byte(format + "/" + endpoint))
+	if err != nil || n == 0 {
+		log.Printf("500: Error writing to HTTP stream: %v, %v %v via %v\n", err, r.Method, r.URL, uip)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+
+}
+
+// handles "/api/plain/tags"
+func apiTagsBaseHandler(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	format := vars["format"]
+
+	uip := getIPFromCtx(r.Context())
+	log.Printf("Request from %v :: %v %v\n", uip, r.Method, r.URL)
+
+	w.Header().Set("Content-Type", htmlutf8)
+	n, err := w.Write([]byte("api/" + format + "/tags"))
+	if err != nil || n == 0 {
+		log.Printf("500: Error writing to HTTP stream: %v, %v %v via %v\n", err, r.Method, r.URL, uip)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+
+}
+
+// handles "/api/plain/tags/[a-zA-Z0-9]+"
+func apiTagsHandler(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	format := vars["format"]
+	tags := vars["tags"]
+
+	uip := getIPFromCtx(r.Context())
+	log.Printf("Request from %v :: %v %v\n", uip, r.Method, r.URL)
+
+	w.Header().Set("Content-Type", htmlutf8)
+	n, err := w.Write([]byte("api/" + format + "/tags/" + tags))
+	if err != nil || n == 0 {
+		log.Printf("500: Error writing to HTTP stream: %v, %v %v via %v\n", err, r.Method, r.URL, uip)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+
+}
+
+// Serving the stylesheet virtually because
+// files aren't served directly.
+func cssHandler(w http.ResponseWriter, r *http.Request) {
+	uip := getIPFromCtx(r.Context())
+	log.Printf("Request from %v :: %v %v\n", uip, r.Method, r.URL)
+
+	// read the raw bytes of the stylesheet
+	css, err := ioutil.ReadFile("assets/style.css")
+	if err != nil {
+		if os.IsNotExist(err) {
+			log.Printf("CSS file does not exist: /css request 404\n")
+			http.Error(w, err.Error(), http.StatusNotFound)
+			return
+		}
+		log.Printf("500: %v\n", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// Get the mod time for the etag header
+	stat, err := os.Stat("assets/style.css")
+	if err != nil {
+		log.Printf("Couldn't stat CSS file to send ETag header: %v\n", err)
+	}
+
+	// Sending the sha256 sum of the modtime in hexadecimal for the ETag header
+	etag := fmt.Sprintf("%x", sha256.Sum256([]byte(stat.ModTime().String())))
+
+	w.Header().Set("ETag", "\""+etag+"\"")
+	w.Header().Set("Content-Type", cssutf8)
+	n, err := w.Write(css)
+	if err != nil || n == 0 {
+		log.Printf("500: Error writing to HTTP stream: %v, %v %v via %v\n", err, r.Method, r.URL, uip)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+}