Support directory installations

- Add web log to HttpContext on first retrieval per req
- Add several DotLiquid filters
- Use int for page numbers
- Update all themes to use rel/abs link and other filters

src/MyWebLog.Domain/DataTypes.fs

@@ -289,8 +289,20 @@ module WebLog =
           timeZone     = ""
         }
     
-    /// Convert a permalink to an absolute URL
-    let absoluteUrl webLog = function Permalink link -> $"{webLog.urlBase}{link}"
+    /// Get the host (including scheme) and extra path from the URL base
+    let hostAndPath webLog =
+        let scheme = webLog.urlBase.Split "://"
+        let host   = scheme[1].Split "/"
+        $"{scheme[0]}://{host[0]}", if host.Length > 1 then $"""/{String.Join ("/", host |> Array.skip 1)}""" else ""
+    
+    /// Generate an absolute URL for the given link
+    let absoluteUrl webLog permalink =
+        $"{webLog.urlBase}/{Permalink.toString permalink}"
+
+    /// Generate a relative URL for the given link
+    let relativeUrl webLog permalink =
+        let _, leadPath = hostAndPath webLog
+        $"{leadPath}/{Permalink.toString permalink}"
     
     /// Convert a date/time to the web log's local date/time
     let localTime webLog (date : DateTime) =

src/MyWebLog.Domain/ViewModels.fs

@@ -400,7 +400,8 @@ type PostListItem =
 
     /// Create a post list item from a post
     static member fromPost (webLog : WebLog) (post : Post) =
-        let inTZ = WebLog.localTime webLog
+        let _, extra = WebLog.hostAndPath webLog
+        let inTZ     = WebLog.localTime   webLog
         { id          = PostId.toString post.id
           authorId    = WebLogUserId.toString post.authorId
           status      = PostStatus.toString   post.status
@@ -408,7 +409,7 @@ type PostListItem =
           permalink   = Permalink.toString post.permalink
           publishedOn = post.publishedOn |> Option.map inTZ |> Option.toNullable
           updatedOn   = inTZ post.updatedOn
-          text        = post.text
+          text        = if extra = "" then post.text else post.text.Replace ("href=\"/", $"href=\"{extra}/")
           categoryIds = post.categoryIds |> List.map CategoryId.toString
           tags        = post.tags
           meta        = post.metadata