added ConditionalHTTPService

README.md

@@ -20,6 +20,13 @@ Config = webconfig.NewWebConfig(<websites' full root path>)
 - Common web settings + security, and URL management options.
 - Keeps a separate file for blocked IP addresses. 
 - Built-in timeout event to reset the Message Banner display value to off.
+- Conditional HTTP Service based on ip address, header, and query string.
+The following example allows only bing and google bots to see /robot.txt:
+
+conditional-http-service [{"rule-type":"ip-address","url-path":"/robot.txt","serve-only-to-criteria":["+http://www.bing.com/bingbot.htm","+http://www.google.com/bot.html"],"http-status-code":404}]]
+
+See *ConditionalHTTPService* and *conditional-http-service* in defs.go
+
 - Built-in Request Validation; usage example:
 ``` go
 isRequestValid, httpErrCode := Config.ValidateHTTPRequest(w, r)

defs.go

@@ -1,5 +1,34 @@
 package webconfig
 
+const (
+	CondHTTPSvc_Header      = "header"
+	CondHTTPSvc_IPAddress   = "ip-address"
+	CondHTTPSvc_QueryString = "query-string"
+)
+
+// ConditionalHTTPService serves an HTTP request according to a
+// condition based on a value in the header, query string or
+// ip address.
+type ConditionalHTTPService struct {
+
+	// RuleType can be: header, query-string, or ip-address
+	RuleType string `json:"rule-type"`
+
+	// URLPath is the relative URL of the request; i.e. /robot.txt
+	URLPath string `json:"url-path"`
+
+	// ServeOnlyToCriteria are the related strings to match. i.e.,
+	// bingbot/2.0; +http://www.bing.com/bingbot.htm and
+	// Googlebot/2.1; +http://www.google.com/bot.html can be
+	// two string elements in the Vaues array that will be used to
+	// match in the Header (User-Agent). For example, if the target url
+	// is /robot.txt; it will only be served to google and bing bots.
+	ServeOnlyToCriteria []string `json:"serve-only-to-criteria"`
+
+	// HTTPStatusCode is http status code that will be retured, if
+	// a match is found. The default is 404 (not found).
+	HTTPStatusCode int `json:"http-status-code"`
+}
 type messageBanner struct {
 	On               bool `json:"on"`
 	SecondsToDisplay int  `json:"seconds-to-display"`
@@ -22,10 +51,12 @@ type tlsFiles struct {
 	CertFilePath string `json:"cert-file-path"`
 	KeyFilePath  string `json:"key-file-path"`
 }
+
 type urlPaths struct {
-	Restrict []string `json:"restrict"`
-	Forward  []string `json:"forward"`
-	Exclude  []string `json:"exclude"`
+	Restrict    []string                 `json:"restrict"`
+	Forward     []string                 `json:"forward"`
+	Exclude     []string                 `json:"exclude"`
+	ServeOnlyTo []ConditionalHTTPService `json:"conditional-http-service"`
 }
 
 // admin defines the IP addresses
@@ -169,22 +200,32 @@ MessageBanner
 # These option to make a portion of your site unavailable for maintenance
 # or other reasons. Each path must begin with a slash (relative path).
 # The following should be the order or evaluation: 
-#       restrict-paths, exclude-paths, forward-paths.
+# restrict-paths, exclude-paths, forward-paths, conditional-http-service.
 URLPaths
    # restrict-paths <url paths separated by comma>
    # e.g.
    # restrict-paths   /gallery,/accounting, /customer-review, /myblog
+   restrict-paths
 
    # with the exclude option, files will be intact in the same location, but not
    # served; the end-user will receive 404 error; or the behaviour can be 
    # customized.
    # exclude-paths /galleryx, /someotherpath
+   exclude-paths
 
    # forward-paths <url-from|url-to-forward paths separated by comma>.
-   # Note that forwarding to a fully qualified url must not be allowed!
+   # Note that forwarding to a fully qualified url must not be allowed.
    # e.g.   
    # forward-paths  /along-name-of-a-blog-page|/latest-blog, /another-along-name-of-a-blog-page|/best-of-blogs, \ 
    #           /and-more-and-more-pages|/yet-the-best-blog
+   forward-paths
+
+   # Conditional HTTP Service serves an HTTP request according to a
+   # condition based on a value in the header, query string or
+   # ip address. If a matching string is found the request will be
+   # e.g. the following only allows the bing and google bots see the robot.txt file.
+   # conditional-http-service [{"rule-type":"header","url-path":"/robot.txt","serve-only-to-criteria":["+http://www.bing.com/bingbot.htm","+http://www.google.com/bot.html"],"http-status-code":404}]
+   conditional-http-service
 
 # HEAD and GET are generally allowed by default.
 HTTP

private.go

@@ -1,6 +1,7 @@
 package webconfig
 
 import (
+	"encoding/json"
 	"fmt"
 	"log"
 	"os"
@@ -266,6 +267,9 @@ func (c *Config) getConfigLeaves(lines []string, i int, section string, keys []s
 					c.URLPaths.Exclude[j] = strings.TrimLeft(c.URLPaths.Exclude[j], " ")
 					c.URLPaths.Exclude[j] = strings.TrimRight(c.URLPaths.Exclude[j], " ")
 				}
+			} else if strings.HasPrefix(l, "conditional-http-service") {
+				s := c.parseCofigLine(l, "conditional-http-service")
+				json.Unmarshal([]byte(s), &c.URLPaths.ServeOnlyTo)
 			}
 		}
 

public.go

@@ -214,7 +214,7 @@ func (c *Config) GetConfig() {
 
 		} else if strings.HasPrefix(lLower, "urlpaths") {
 
-			keys := []string{"restrict-paths", "exclude-paths", "forward-paths"}
+			keys := []string{"restrict-paths", "exclude-paths", "forward-paths", "conditional-http-service"}
 			i++
 			i = c.getConfigLeaves(line, i, "URLPaths", keys)
 		}

validate.go

@@ -33,7 +33,7 @@ func (c *Config) ValidateHTTPRequest(w http.ResponseWriter, r *http.Request) (bo
 		return false, http.StatusMethodNotAllowed
 	}
 
-	// This is the order: restrict-paths, exclude-path, forward-paths
+	// This is the order: restrict-paths, exclude-path, forward-paths, conditional-http-service
 
 	// restrict-paths
 	for i := 0; i < len(c.URLPaths.Restrict); i++ {
@@ -78,5 +78,50 @@ func (c *Config) ValidateHTTPRequest(w http.ResponseWriter, r *http.Request) (bo
 		}
 	}
 
+	// conditional-http-service
+	ip := strings.Split(strings.Replace(strings.Replace(r.RemoteAddr, "[", "", -1), "]", "", -1), ":")[0]
+	qs := r.URL.RawQuery
+
+	for i := 0; i < len(c.URLPaths.ServeOnlyTo); i++ {
+		if rPath == c.URLPaths.ServeOnlyTo[i].URLPath {
+			// check headers
+			if c.URLPaths.ServeOnlyTo[i].RuleType == CondHTTPSvc_Header {
+				for _, v := range r.Header {
+					for j := 0; j < len(c.URLPaths.ServeOnlyTo[i].ServeOnlyToCriteria); j++ {
+						m := c.URLPaths.ServeOnlyTo[i].ServeOnlyToCriteria[j]
+						for k := 0; k < len(v); k++ {
+							if strings.Contains(v[k], m) {
+								// The caller can view the page - as its request header
+								// has a value that matches the ServerOnlyTo critiera
+								return true, 0
+							}
+						}
+					}
+				}
+			}
+
+			// check IP address and query string
+			for j := 0; j < len(c.URLPaths.ServeOnlyTo[i].ServeOnlyToCriteria); j++ {
+				if c.URLPaths.ServeOnlyTo[i].ServeOnlyToCriteria[j] == ip || strings.Contains(qs, c.URLPaths.ServeOnlyTo[i].ServeOnlyToCriteria[j]) {
+					// The caller can view the page - as its request header
+					// has a value that matches the ServerOnlyTo critiera
+					return true, 0
+				}
+			}
+
+			// If we get here, it means that:
+			//   1. there is a rule for the current r.Path
+			//   2. there is no match found to allow the client to recieve the content
+			// so, return error
+			errCode := c.URLPaths.ServeOnlyTo[i].HTTPStatusCode
+
+			if errCode < 1 {
+				errCode = 404 // default error code
+			}
+
+			return false, errCode
+		}
+	}
+
 	return true, 0
 }