Check http protocol to determine if really http or no connection

If the publisher did not responding to a query for libp2phttp and the publisher address is an HTTP address, then make an HTTP request to determine if the protocol really is HTTP or if the publisher if just not responding.

pkg/provider/provider.go

@@ -2,15 +2,18 @@ package provider
 
 import (
 	"bufio"
+	"context"
 	"errors"
 	"fmt"
+	"net/http"
 	"os"
 	"strings"
 	"time"
 
 	"github.com/ipfs/go-cid"
 	"github.com/ipni/go-libipni/dagsync/ipnisync"
 	"github.com/ipni/go-libipni/find/model"
+	"github.com/ipni/go-libipni/maurl"
 	"github.com/ipni/go-libipni/mautil"
 	"github.com/ipni/go-libipni/pcache"
 	"github.com/ipni/ipni-cli/pkg/dtrack"
@@ -357,7 +360,7 @@ func showProviderInfo(cctx *cli.Context, pinfo *model.ProviderInfo) {
 				proto = fmt.Sprintf("Error: %s", err)
 			} else {
 				defer p2pHost.Close()
-				proto, err = getProtocol(*pinfo.Publisher, p2pHost)
+				proto, err = getProtocol(cctx.Context, *pinfo.Publisher, p2pHost)
 				if err != nil {
 					proto = fmt.Sprintf("Error: %s", err)
 				}
@@ -399,7 +402,7 @@ func showProviderInfo(cctx *cli.Context, pinfo *model.ProviderInfo) {
 	fmt.Println()
 }
 
-func getProtocol(peerInfo peer.AddrInfo, p2pHost host.Host) (string, error) {
+func getProtocol(ctx context.Context, peerInfo peer.AddrInfo, p2pHost host.Host) (string, error) {
 	clientHost := &libp2phttp.Host{
 		StreamHost: p2pHost,
 	}
@@ -426,6 +429,20 @@ func getProtocol(peerInfo peer.AddrInfo, p2pHost host.Host) (string, error) {
 		if len(httpAddrs) == 0 {
 			return "data-transfer/graphsync", nil
 		}
+		u, err := maurl.ToURL(peerInfo.Addrs[0])
+		if err != nil {
+			return "", err
+		}
+		fetchURL := u.JoinPath(ipnisync.IPNIPath, "head")
+		req, err := http.NewRequestWithContext(ctx, "GET", fetchURL.String(), nil)
+		if err != nil {
+			return "", err
+		}
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			return "", err
+		}
+		resp.Body.Close()
 		return "http", nil
 	}
 	return "libp2phttp", nil