initial commit

internal/reverseproxy/proxy.go

@@ -0,0 +1,133 @@
+package reverseproxy
+
+import (
+	"fmt"
+	"github.com/labstack/echo/v4"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"regexp"
+	"strings"
+	"tesseract/internal/service"
+)
+
+type ReverseProxy struct {
+	*echo.Echo
+
+	services    service.Services
+	httpProxies map[string]*httputil.ReverseProxy
+}
+
+type portMapping struct {
+	subdomain     string
+	containerPort int
+	hostPort      int
+}
+
+const keyReverseProxy = "reverseProxy"
+
+func New(services service.Services) *ReverseProxy {
+	e := echo.New()
+	proxy := &ReverseProxy{
+		e,
+		services,
+		make(map[string]*httputil.ReverseProxy),
+	}
+
+	e.Any("/*", proxy.handleRequest)
+
+	return proxy
+}
+
+func From(c echo.Context) *ReverseProxy {
+	return c.Get(keyReverseProxy).(*ReverseProxy)
+}
+
+func (p *ReverseProxy) Start() error {
+	rows, err := p.services.Database.Query("SELECT container_port, host_port, subdomain FROM port_mappings;")
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+
+	var mappings []portMapping
+	for rows.Next() {
+		mapping := portMapping{}
+		err = rows.Scan(&mapping.containerPort, &mapping.hostPort, &mapping.subdomain)
+		if err != nil {
+			return err
+		}
+	}
+
+	for _, m := range mappings {
+		if m.subdomain == "" {
+			continue
+		}
+
+		u, err := url.Parse(fmt.Sprintf("http://localhost:%d", m.hostPort))
+		if err != nil {
+			continue
+		}
+
+		proxy := httputil.NewSingleHostReverseProxy(u)
+		p.httpProxies[m.subdomain] = proxy
+	}
+
+	return nil
+}
+
+func (p *ReverseProxy) Middleware() echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			c.Set(keyReverseProxy, p)
+			return next(c)
+		}
+	}
+}
+
+func (p *ReverseProxy) ShouldHandleRequest(c echo.Context) bool {
+	config := p.services.Config
+	h := strings.Replace(config.HostName, ".", "\\.", -1)
+	reg, err := regexp.Compile(".*\\." + h)
+	if err != nil {
+		return false
+	}
+	return reg.MatchString(c.Request().Host)
+}
+
+func (p *ReverseProxy) handleRequest(c echo.Context) error {
+	req := c.Request()
+	res := c.Response()
+	config := p.services.Config
+
+	h := strings.Replace(config.HostName, ".", "\\.", -1)
+	reg, err := regexp.Compile(fmt.Sprintf("(?P<subdomain>.*)\\.%v", h))
+	if err != nil {
+		return err
+	}
+
+	matches := reg.FindStringSubmatch(req.Host)
+	if len(matches) == 0 {
+		return echo.NewHTTPError(http.StatusNotFound)
+	}
+
+	var subdomain string
+	for i, name := range reg.SubexpNames() {
+		if i != 0 && name == "subdomain" {
+			subdomain = matches[i]
+			break
+		}
+	}
+	if subdomain == "" {
+		return echo.NewHTTPError(http.StatusNotFound)
+	}
+
+	proxy, ok := p.httpProxies[subdomain]
+	if !ok {
+		return echo.NewHTTPError(http.StatusNotFound)
+	}
+
+	proxy.ServeHTTP(res, req)
+
+	return nil
+}