multi-protocol client

Fixes #4

7 files changed, 112 insertions, 7 deletions

diff --git a/README.md b/README.md
index f07fe61..56fb71f 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,7 @@ sliderule is carefully structured as composable building blocks. The top-level p
 * a "Server" interface type
 * a "Handler" abstraction
 * a "Middleware" abstraction
+* a "Client" which handles all the protocols known to sliderule
 * some useful Handler wrappers: a router, request filtering, falling through a list of handlers
 
 ## Protocols
diff --git a/client.go b/client.go
new file mode 100644
index 0000000..3631bc5
--- /dev/null
+++ b/client.go
@@ -0,0 +1,87 @@
+package sliderule
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	neturl "net/url"
+
+	"tildegit.org/tjp/sliderule/finger"
+	"tildegit.org/tjp/sliderule/gemini"
+	"tildegit.org/tjp/sliderule/gopher"
+	"tildegit.org/tjp/sliderule/internal/types"
+	"tildegit.org/tjp/sliderule/spartan"
+)
+
+type protocolClient interface {
+	RoundTrip(*Request) (*Response, error)
+	IsRedirect(*Response) bool
+}
+
+// Client is a multi-protocol client which handles all protocols known to sliderule.
+type Client struct {
+	MaxRedirects int
+
+	protos map[string]protocolClient
+}
+
+const DefaultMaxRedirects int = 2
+
+var ExceededMaxRedirects = errors.New("Client: exceeded MaxRedirects")
+
+// NewClient builds a Client object.
+//
+// tlsConf may be nil, in which case gemini requests connections will not be made
+// with any client certificate.
+func NewClient(tlsConf *tls.Config) Client {
+	return Client{
+		protos: map[string]protocolClient{
+			"finger":  finger.Client{},
+			"gopher":  gopher.Client{},
+			"gemini":  gemini.NewClient(tlsConf),
+			"spartan": spartan.NewClient(),
+		},
+		MaxRedirects: DefaultMaxRedirects,
+	}
+}
+
+// RoundTrip sends a single request and returns the repsonse.
+//
+// If the response is a redirect it will be returned, rather than fetched.
+func (c Client) RoundTrip(request *Request) (*Response, error) {
+	pc, ok := c.protos[request.Scheme]
+	if !ok {
+		return nil, fmt.Errorf("unrecognized protocol: %s", request.Scheme)
+	}
+	return pc.RoundTrip(request)
+}
+
+// Fetch collects a resource from a URL including following any redirects.
+func (c Client) Fetch(url string) (*Response, error) {
+	u, err := neturl.Parse(url)
+	if err != nil {
+		return nil, err
+	}
+
+	for i := 0; i <= c.MaxRedirects; i += 1 {
+		response, err := c.RoundTrip(&types.Request{URL: u})
+		if err != nil {
+			return nil, err
+		}
+
+		if !c.protos[u.Scheme].IsRedirect(response) {
+			return response, nil
+		}
+
+		prev := u
+		u, err = neturl.Parse(response.Meta.(string))
+		if err != nil {
+			return nil, err
+		}
+		if u.Scheme == "" {
+			u.Scheme = prev.Scheme
+		}
+	}
+
+	return nil, ExceededMaxRedirects
+}
diff --git a/finger/client.go b/finger/client.go
index 75a382f..bd1e3bf 100644
--- a/finger/client.go
+++ b/finger/client.go
@@ -37,7 +37,12 @@ func (c Client) RoundTrip(request *types.Request) (*types.Response, error) {
 	request.RemoteAddr = conn.RemoteAddr()
 	request.TLSState = nil
 
-	if _, err := conn.Write([]byte(strings.TrimPrefix(request.Path, "/") + "\r\n")); err != nil {
+	username := request.User.String()
+	if username == "" {
+		username = strings.TrimPrefix(request.Path, "/")
+	}
+
+	if _, err := conn.Write([]byte(username + "\r\n")); err != nil {
 		return nil, err
 	}
 
@@ -57,3 +62,5 @@ func (c Client) Fetch(query string) (*types.Response, error) {
 	}
 	return c.RoundTrip(req)
 }
+
+func (c Client) IsRedirect(_ *types.Response) bool { return false }
diff --git a/gemini/client.go b/gemini/client.go
index 34d5839..0a621dd 100644
--- a/gemini/client.go
+++ b/gemini/client.go
@@ -54,7 +54,7 @@ func (client Client) RoundTrip(request *types.Request) (*types.Response, error)
 	}
 
 	tlsConf := client.tlsConf
-	if (tlsConf == nil) {
+	if tlsConf == nil {
 		tlsConf = &tls.Config{InsecureSkipVerify: true}
 	}
 
@@ -102,12 +102,12 @@ func (c Client) Fetch(url string) (*types.Response, error) {
 		if err != nil {
 			return nil, err
 		}
-		if ResponseCategoryForStatus(response.Status) != ResponseCategoryRedirect {
+		if !c.IsRedirect(response) {
 			return response, nil
 		}
 
 		prev := u
-		u, err = neturl.Parse(url)
+		u, err = neturl.Parse(response.Meta.(string))
 		if err != nil {
 			return nil, err
 		}
@@ -116,3 +116,7 @@ func (c Client) Fetch(url string) (*types.Response, error) {
 
 	return nil, ExceededMaxRedirects
 }
+
+func (c Client) IsRedirect(response *types.Response) bool {
+	return ResponseCategoryForStatus(response.Status) == ResponseCategoryRedirect
+}
diff --git a/gemini/response.go b/gemini/response.go
index 13f493a..b3e53aa 100644
--- a/gemini/response.go
+++ b/gemini/response.go
@@ -44,7 +44,7 @@ const (
 )
 
 func ResponseCategoryForStatus(status types.Status) ResponseCategory {
-	return ResponseCategory(status / 10)
+	return ResponseCategory((status / 10) * 10)
 }
 
 const (
diff --git a/gopher/client.go b/gopher/client.go
index 5ef54ff..a5c4228 100644
--- a/gopher/client.go
+++ b/gopher/client.go
@@ -63,3 +63,5 @@ func (c Client) Fetch(url string) (*types.Response, error) {
 	}
 	return c.RoundTrip(&types.Request{URL: u})
 }
+
+func (c Client) IsRedirect(_ *types.Response) bool { return false }
diff --git a/spartan/client.go b/spartan/client.go
index e3025ee..affcf95 100644
--- a/spartan/client.go
+++ b/spartan/client.go
@@ -100,12 +100,12 @@ func (c Client) Fetch(url string) (*types.Response, error) {
 		if err != nil {
 			return nil, err
 		}
-		if response.Status != StatusRedirect {
+		if !c.IsRedirect(response) {
 			return response, nil
 		}
 
 		prev := u
-		u, err = neturl.Parse(url)
+		u, err = neturl.Parse(response.Meta.(string))
 		if err != nil {
 			return nil, err
 		}
@@ -115,6 +115,10 @@ func (c Client) Fetch(url string) (*types.Response, error) {
 	return nil, ExceededMaxRedirects
 }
 
+func (c Client) IsRedirect(response *types.Response) bool {
+	return response.Status == StatusRedirect
+}
+
 type devnull struct{}
 
 func (_ devnull) Read(p []byte) (int, error) {