Daniel J. Summers 5fb3a73dcf Add user created and last seen on (#19)
- Updated view models / interfaces per F# naming guidelines
2022-07-17 23:10:30 -04:00

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/// Handlers to manipulate uploaded files
module MyWebLog.Handlers.Upload
open System
open System.IO
open Giraffe
open Microsoft.AspNetCore.Http
open Microsoft.Net.Http.Headers
open MyWebLog
/// Helper functions for this module
[<AutoOpen>]
module private Helpers =
open Microsoft.AspNetCore.StaticFiles
/// A MIME type mapper instance to use when serving files from the database
let mimeMap = FileExtensionContentTypeProvider ()
/// A cache control header that instructs the browser to cache the result for no more than 30 days
let cacheForThirtyDays =
let hdr = CacheControlHeaderValue()
hdr.MaxAge <- Some (TimeSpan.FromDays 30) |> Option.toNullable
hdr
/// Shorthand for the directory separator
let slash = Path.DirectorySeparatorChar
/// The base directory where uploads are stored, relative to the executable
let uploadDir = Path.Combine ("wwwroot", "upload")
/// Determine if the file has been modified since the date/time specified by the If-Modified-Since header
let checkModified since (ctx : HttpContext) : HttpHandler option =
match ctx.Request.Headers.IfModifiedSince with
| it when it.Count < 1 -> None
| it when since > DateTime.Parse it[0] -> None
| _ -> Some (setStatusCode 304 >=> setBodyFromString "Not Modified")
open Microsoft.AspNetCore.Http.Headers
/// Derive a MIME type based on the extension of the file
let deriveMimeType path =
match mimeMap.TryGetContentType path with true, typ -> typ | false, _ -> "application/octet-stream"
/// Send a file, caching the response for 30 days
let sendFile updatedOn path (data : byte[]) : HttpHandler = fun next ctx ->
let headers = ResponseHeaders ctx.Response.Headers
headers.ContentType <- (deriveMimeType >> MediaTypeHeaderValue) path
headers.CacheControl <- cacheForThirtyDays
let stream = new MemoryStream (data)
streamData true stream None (Some (DateTimeOffset updatedOn)) next ctx
// GET /upload/{web-log-slug}/{**path}
let serve (urlParts : string seq) : HttpHandler = fun next ctx -> task {
let webLog = ctx.WebLog
let parts = (urlParts |> Seq.skip 1 |> Seq.head).Split '/'
let slug = Array.head parts
if slug = webLog.slug then
// Static file middleware will not work in subdirectories; check for an actual file first
let fileName = Path.Combine ("wwwroot", (Seq.head urlParts)[1..])
if File.Exists fileName then
return! streamFile true fileName None None next ctx
else
let path = String.Join ('/', Array.skip 1 parts)
match! ctx.Data.Upload.FindByPath path webLog.id with
| Some upload ->
match checkModified upload.updatedOn ctx with
| Some threeOhFour -> return! threeOhFour next ctx
| None -> return! sendFile upload.updatedOn path upload.data next ctx
| None -> return! Error.notFound next ctx
else
return! Error.notFound next ctx
}
// ADMIN
open System.Text.RegularExpressions
open DotLiquid
open MyWebLog.ViewModels
/// Turn a string into a lowercase URL-safe slug
let makeSlug it = ((Regex """\s+""").Replace ((Regex "[^A-z0-9 ]").Replace (it, ""), "-")).ToLowerInvariant ()
// GET /admin/uploads
let list : HttpHandler = requireAccess Author >=> fun next ctx -> task {
let webLog = ctx.WebLog
let! dbUploads = ctx.Data.Upload.FindByWebLog webLog.id
let diskUploads =
let path = Path.Combine (uploadDir, webLog.slug)
try
Directory.EnumerateFiles (path, "*", SearchOption.AllDirectories)
|> Seq.map (fun file ->
let name = Path.GetFileName file
let create =
match File.GetCreationTime (Path.Combine (path, file)) with
| dt when dt > DateTime.UnixEpoch -> Some dt
| _ -> None
{ DisplayUpload.Id = ""
Name = name
Path = file.Replace($"{path}{slash}", "").Replace(name, "").Replace (slash, '/')
UpdatedOn = create
Source = UploadDestination.toString Disk
})
|> List.ofSeq
with
| :? DirectoryNotFoundException -> [] // This is fine
| ex ->
warn "Upload" ctx $"Encountered {ex.GetType().Name} listing uploads for {path}:\n{ex.Message}"
[]
let allFiles =
dbUploads
|> List.map (DisplayUpload.fromUpload webLog Database)
|> List.append diskUploads
|> List.sortByDescending (fun file -> file.UpdatedOn, file.Path)
return!
Hash.FromAnonymousObject {|
page_title = "Uploaded Files"
csrf = ctx.CsrfTokenSet
files = allFiles
|}
|> viewForTheme "admin" "upload-list" next ctx
}
// GET /admin/upload/new
let showNew : HttpHandler = requireAccess Author >=> fun next ctx ->
Hash.FromAnonymousObject {|
page_title = "Upload a File"
csrf = ctx.CsrfTokenSet
destination = UploadDestination.toString ctx.WebLog.uploads
|}
|> viewForTheme "admin" "upload-new" next ctx
/// Redirect to the upload list
let showUploads : HttpHandler =
redirectToGet "admin/uploads"
// POST /admin/upload/save
let save : HttpHandler = requireAccess Author >=> fun next ctx -> task {
if ctx.Request.HasFormContentType && ctx.Request.Form.Files.Count > 0 then
let upload = Seq.head ctx.Request.Form.Files
let fileName = String.Concat (makeSlug (Path.GetFileNameWithoutExtension upload.FileName),
Path.GetExtension(upload.FileName).ToLowerInvariant ())
let localNow = WebLog.localTime ctx.WebLog DateTime.Now
let year = localNow.ToString "yyyy"
let month = localNow.ToString "MM"
let! form = ctx.BindFormAsync<UploadFileModel> ()
match UploadDestination.parse form.Destination with
| Database ->
use stream = new MemoryStream ()
do! upload.CopyToAsync stream
let file =
{ id = UploadId.create ()
webLogId = ctx.WebLog.id
path = Permalink $"{year}/{month}/{fileName}"
updatedOn = DateTime.UtcNow
data = stream.ToArray ()
}
do! ctx.Data.Upload.Add file
| Disk ->
let fullPath = Path.Combine (uploadDir, ctx.WebLog.slug, year, month)
let _ = Directory.CreateDirectory fullPath
use stream = new FileStream (Path.Combine (fullPath, fileName), FileMode.Create)
do! upload.CopyToAsync stream
do! addMessage ctx { UserMessage.success with Message = $"File uploaded to {form.Destination} successfully" }
return! showUploads next ctx
else
return! RequestErrors.BAD_REQUEST "Bad request; no file present" next ctx
}
// POST /admin/upload/{id}/delete
let deleteFromDb upId : HttpHandler = requireAccess WebLogAdmin >=> fun next ctx -> task {
match! ctx.Data.Upload.Delete (UploadId upId) ctx.WebLog.id with
| Ok fileName ->
do! addMessage ctx { UserMessage.success with Message = $"{fileName} deleted successfully" }
return! showUploads next ctx
| Error _ -> return! Error.notFound next ctx
}
/// Remove a directory tree if it is empty
let removeEmptyDirectories (webLog : WebLog) (filePath : string) =
let mutable path = Path.GetDirectoryName filePath
let mutable finished = false
while (not finished) && path > "" do
let fullPath = Path.Combine (uploadDir, webLog.slug, path)
if Directory.EnumerateFileSystemEntries fullPath |> Seq.isEmpty then
Directory.Delete fullPath
path <- String.Join(slash, path.Split slash |> Array.rev |> Array.skip 1 |> Array.rev)
else finished <- true
// POST /admin/upload/delete/{**path}
let deleteFromDisk urlParts : HttpHandler = requireAccess WebLogAdmin >=> fun next ctx -> task {
let filePath = urlParts |> Seq.skip 1 |> Seq.head
let path = Path.Combine (uploadDir, ctx.WebLog.slug, filePath)
if File.Exists path then
File.Delete path
removeEmptyDirectories ctx.WebLog filePath
do! addMessage ctx { UserMessage.success with Message = $"{filePath} deleted successfully" }
return! showUploads next ctx
else return! Error.notFound next ctx
}