X-Git-Url: https://git.xandkar.net/?a=blobdiff_plain;f=tt.rkt;h=6e227283e08694972a02baf4a703f3661e680076;hb=5fef9856f51272827b23cbf47f3b61d3a51abef0;hp=6ce0bd17e2ce2b4b3d2218af16cf38e916c4b2d7;hpb=50f0609d3fd9ea1ab8c37907c7d7ee7a80546e0a;p=tt.git

diff --git a/tt.rkt b/tt.rkt
index 6ce0bd1..6e22728 100644
--- a/tt.rkt
+++ b/tt.rkt
@@ -27,6 +27,26 @@
   (∀ (α β) (U (cons 'ok α)
               (cons 'error β))))
 
+(struct Hist
+        ([freq : Nonnegative-Integer]
+         [last : Nonnegative-Integer])
+        #:transparent)
+
+(define-type Url-Nick-Hist
+  (Immutable-HashTable Url (Immutable-HashTable (Option String) Hist)))
+
+(struct User
+        ([uri  : Url]
+         [nick : (Option String)]))
+
+(struct User-Agent
+        ([user : User]
+         [prog : Prog]))
+
+(struct Prog
+        ([name    : String]
+         [version : String]))
+
 (struct Msg
         ([ts-epoch   : Integer]
          [ts-orig    : String]
@@ -41,11 +61,73 @@
          [comment : (Option String)])
         #:transparent)
 
-(struct Resp
-        ([status-line : String]
-         [headers     : (Listof Bytes)]
-         [body-input  : Input-Port])
-        #:transparent)
+(: prog Prog)
+(define prog
+  (Prog "tt" (info:#%info-lookup 'version)))
+
+(: user-default User)
+(define user-default
+  (User (string->url "https://github.com/xandkar/tt") #f))
+
+(: user->str (-> User String))
+(define (user->str user)
+  (match-define (User u0 n) user)
+  (define u (url->string u0))
+  (if n
+      (format "+~a; @~a" u n)
+      (format "+~a"      u  )))
+
+(: user-agent->str (-> User-Agent String))
+(define (user-agent->str ua)
+  (match-define (User-Agent u p) ua)
+  (format "~a/~a (~a)" (Prog-name p) (Prog-version p) (user->str u)))
+
+(: user->user-agent User)
+(define (user->user-agent user)
+  (User-Agent user prog))
+
+(: user-agent-str String)
+(define user-agent-str
+  (user-agent->str (user->user-agent user-default)))
+
+(: set-user-agent-str (-> Path-String Void))
+(define (set-user-agent-str filename)
+  (set! user-agent-str (user-agent->str (user->user-agent (file->user filename))))
+  (log-info "User-Agent string is now set to: ~v" user-agent-str))
+
+(: file->user (-> Path-String User))
+(define (file->user filename)
+  (if (file-exists? filename)
+      (match (file->peers filename)
+        [(list p)
+         (log-info
+           "User-Agent. Found one peer in file: ~v. Using the found peer: ~a"
+           filename
+           (peer->str p))
+         (peer->user p)]
+        [(list* p _)
+         (log-warning
+           "User-Agent. Multiple peers in file: ~v. Picking arbitrary: ~a"
+           filename
+           (peer->str p))
+         (peer->user p)]
+        ['()
+         (log-warning
+           "User-Agent. No peers found in file: ~v. Using the default user: ~a"
+           filename
+           user-default)
+         user-default])
+      (begin
+        (log-warning
+          "User-Agent. File doesn't exist: ~v. Using the default user: ~a"
+          filename
+          user-default)
+        user-default)))
+
+(: peer->user (-> Peer User))
+(define (peer->user p)
+  (match-define (Peer n u _ _) p)
+  (User u n))
 
 (: peers-equal? (-> Peer Peer Boolean))
 (define (peers-equal? p1 p2)
@@ -74,13 +156,14 @@
 ;
 ; TODO Investigate why and make a minimal reproducible test case.
 
-(define (peers-union . peer-sets)
+(: peers-merge (-> (Listof Peer) * (Listof Peer)))
+(define (peers-merge . peer-sets)
   (define groups
     (foldl
       (λ (p groups)
          (hash-update groups (Peer-uri-str p) (λ (group) (cons p group)) '()))
       (hash)
-      (append* (map set->list peer-sets))))
+      (append* peer-sets)))
   (define (merge peers)
     (match peers
       ['() (raise 'impossible)]
@@ -89,14 +172,17 @@
        (let* ([n1 (Peer-nick p1)]
               [n2 (Peer-nick p2)]
               [p (cond
-                   [(and (not n1) (not n2)) p1]
-                   [(and      n1       n2 ) p1]
+                   ; TODO Try to pick from nicks db: preferred, otherwise seen
+                   [(and (not n1) (not n2)) p1] ; TODO update with most-common nick
+                   [(and      n1       n2 ) p1] ; TODO compare which is more-common
                    [(and      n1  (not n2)) p1]
                    [(and (not n1)      n2)  p2]
                    [else
                      (raise 'impossible)])])
          (merge (cons p ps)))]))
-  (make-immutable-peers (map merge (hash-values groups))))
+  (sort (map merge (hash-values groups))
+        (match-lambda**
+          [((Peer _ _ u1 _) (Peer _ _ u2 _)) (string<? u1 u2)])))
 
 (module+ test
   (let* ([u1 "http://foo/bar"]
@@ -104,16 +190,17 @@
          [p1 (Peer #f (string->url u1) u1 #f)]
          [p2 (Peer "a" (string->url u1) u1 #f)]
          [p3 (Peer "b" (string->url u2) u2 #f)]
-         [s1 (make-immutable-peers (list p1))]
-         [s2 (make-immutable-peers (list p2 p3))])
-    (check-true (peers? (peers-union s1 s2)))
-    (check-true (peers? (peers-union s2 s1)))
-    (check-equal? (list p3 p2) (set->list (peers-union s1 s2)))
-    (check-equal? (list p3 p2) (set->list (peers-union s2 s1)))))
+         [s1 (list p1)]
+         [s2 (list p2 p3)])
+    (check-equal? (list p3 p2) (peers-merge s1 s2))
+    (check-equal? (list p3 p2) (peers-merge s2 s1))))
 
 (: tt-home-dir Path-String)
 (define tt-home-dir (build-path (expand-user-path "~") ".tt"))
 
+(: pub-peers-dir Path-String)
+(define pub-peers-dir (build-path tt-home-dir "peers"))
+
 (: concurrent-filter-map (∀ (α β) (-> Natural (-> α β) (Listof α) (Listof β))))
 (define (concurrent-filter-map num-workers f xs)
   ; TODO preserve order of elements OR communicate that reorder is expected
@@ -317,6 +404,8 @@
 (module+ test
   (check-equal? (str->lines "abc\ndef\n\nghi") '("abc" "def" "ghi")))
 
+; TODO Should return 2 things: 1) msgs; 2) metadata parsed from comments
+; TODO Update peer nick based on metadata?
 (: str->msgs (-> Peer String (Listof Msg)))
 (define (str->msgs peer str)
   (filter-map (λ (line) (str->msg peer line))
@@ -431,15 +520,16 @@
 (define (filter-comments lines)
   (filter-not (λ (line) (string-prefix? line "#")) lines))
 
-(: str->peers (-> String (Setof Peer)))
+(: str->peers (-> String (Listof Peer)))
 (define (str->peers str)
-  (make-immutable-peers (filter-map str->peer (filter-comments (str->lines str)))))
+  (filter-map str->peer (filter-comments (str->lines str))))
 
-(: peers->file (-> (Setof Peers) Path-String Void))
+(: peers->file (-> (Listof Peers) Path-String Void))
 (define (peers->file peers path)
+  (make-parent-directory* path)
   (display-lines-to-file
     (map peer->str
-         (sort (set->list peers)
+         (sort peers
                (match-lambda**
                  [((Peer n1 _ _ _) (Peer n2 _ _ _))
                   (string<? (if n1 n1 "")
@@ -447,13 +537,13 @@
     path
     #:exists 'replace))
 
-(: file->peers (-> Path-String (Setof Peer)))
+(: file->peers (-> Path-String (Listof Peer)))
 (define (file->peers file-path)
   (if (file-exists? file-path)
       (str->peers (file->string file-path))
       (begin
         (log-warning "File does not exist: ~v" (path->string file-path))
-        (make-immutable-peers))))
+        '())))
 
 (define re-rfc2822
   #px"^(Mon|Tue|Wed|Thu|Fri|Sat|Sun), ([0-9]{2}) (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) ([0-9]{4}) ([0-2][0-9]):([0-6][0-9]):([0-6][0-9]) GMT")
@@ -492,21 +582,6 @@
     [_
       #f]))
 
-(: user-agent String)
-(define user-agent
-  (let*
-    ([prog-name      "tt"]
-     [prog-version   (info:#%info-lookup 'version)]
-     [prog-uri       "https://github.com/xandkar/tt"]
-     [user-peer-file (build-path tt-home-dir "me")]
-     [user
-       (if (file-exists? user-peer-file)
-           (match (set-first (file->peers user-peer-file))
-             [(Peer #f _ u _) (format "+~a"      u  )]
-             [(Peer  n _ u _) (format "+~a; @~a" u n)])
-           (format "+~a" prog-uri))])
-    (format "~a/~a (~a)" prog-name prog-version user)))
-
 (: header-get (-> (Listof Bytes) Bytes (Option Bytes)))
 (define (header-get headers name)
   (match (filter-map (curry extract-field name) headers)
@@ -517,6 +592,9 @@
    (-> Url (Listof (U Bytes String)) Input-Port
        (U 'skipped-cached 'downloaded-new))) ; TODO 'ok|'error ?
 (define (uri-download-from-port u headers body-input)
+   ; TODO Update message db from here? or where?
+   ; - 1st try can just be an in-memory set that gets written-to
+   ;   and read-from disk as a whole.
   (define u-str (url->string u))
   (log-debug "uri-download-from-port ~v into ~v" u-str cached-object-path)
   (define cached-object-path (url->cache-object-path u))
@@ -576,19 +654,6 @@
                (channel-put timeout-chan '(error . timeout)))))
   (define result-thread
     (thread (λ ()
-               ; XXX We timeout getting a response, but body download could
-               ; also take a long time and we might want to time that out as
-               ; well, but then we may end-up with partially downloaded
-               ; objects. But that could happen anyway if the server drops the
-               ; connection for whatever reason.
-               ;
-               ; Maybe that is OK once we start treating the
-               ; downloaded object as an addition to the stored set of
-               ; messages, rather than the final set of messages.
-
-               ; TODO message db
-               ; - 1st try can just be an in-memory set that gets written-to
-               ;   and read-from disk as a whole.
                (define result
                  (with-handlers
                    ; TODO Maybe name each known errno? (exn:fail:network:errno-errno e)
@@ -599,32 +664,27 @@
                    (define-values (status-line headers body-input)
                      (http-sendrecv/url
                        u
-                       #:headers (list (format "User-Agent: ~a" user-agent))))
-                   `(ok . ,(Resp status-line headers body-input))))
+                       #:headers (list (format "User-Agent: ~a" user-agent-str))))
+                   (log-debug "headers: ~v" headers)
+                   (log-debug "status-line: ~v" status-line)
+                   (define status
+                     (string->number (second (string-split (bytes->string/utf-8 status-line)))))
+                   (log-debug "status: ~v" status)
+                   (let ([result
+                           ; TODO Handle redirects.
+                           ; TODO Should a redirect update a peer URL?
+                           (match status
+                             [200
+                               `(ok . ,(uri-download-from-port u headers body-input))]
+                             [_
+                               `(error . (http-not-ok . ,status))])])
+                     (close-input-port body-input)
+                     result)))
                (channel-put result-chan result))))
-  (define result
-    (sync timeout-chan
-          result-chan))
+  (define result (sync timeout-chan result-chan))
   (kill-thread result-thread)
   (kill-thread timeout-thread)
-  (match result
-    [(cons 'error _)
-     result]
-    [(cons 'ok (Resp status-line headers body-input))
-     (log-debug "headers: ~v" headers)
-     (log-debug "status-line: ~v" status-line)
-     (define status
-       (string->number (second (string-split (bytes->string/utf-8 status-line)))))
-     (log-debug "status: ~v" status)
-     ; TODO Handle redirects. Should be within same timeout as req and body.
-     (let ([result
-             (match status
-               [200
-                 `(ok . ,(uri-download-from-port u headers body-input))]
-               [_
-                 `(error . (http . ,status))])])
-       (close-input-port body-input)
-       result)]))
+  result)
 
 (: timeline-print (-> Out-Format (Listof Msg) Void))
 (define (timeline-print out-format timeline)
@@ -666,12 +726,12 @@
             result)
   result)
 
-(: timeline-download (-> Integer Positive-Float (Setof Peer) Void))
+(: timeline-download (-> Integer Positive-Float (Listof Peer) Void))
 (define (timeline-download num-workers timeout peers)
   (define results
     (concurrent-filter-map num-workers
                            (λ (p) (cons p (peer-download timeout p)))
-                           (set->list peers)))
+                           peers))
   (define peers-ok
     (filter-map (match-lambda
                   [(cons p (cons 'ok _)) p]
@@ -684,12 +744,12 @@
                   [(cons p (cons 'error e))
                    (struct-copy Peer p [comment (format "~s" e)])])
                 results))
-  (peers->file peers-ok (build-path tt-home-dir "peers-last-downloaded-ok"))
-  (peers->file peers-err (build-path tt-home-dir "peers-last-downloaded-err")))
+  (peers->file peers-ok (build-path tt-home-dir "peers-last-downloaded-ok.txt"))
+  (peers->file peers-err (build-path tt-home-dir "peers-last-downloaded-err.txt")))
 
-(: peers->timeline (-> (Setof Peer) (Listof Msg)))
+(: peers->timeline (-> (Listof Peer) (Listof Msg)))
 (define (peers->timeline peers)
-  (append* (filter-map peer->msgs (set->list peers))))
+  (append* (filter-map peer->msgs peers)))
 
 (: timeline-sort (-> (Listof Msg) timeline-order (Listof Msgs)))
 (define (timeline-sort msgs order)
@@ -699,11 +759,11 @@
   (sort msgs (λ (a b) (cmp (Msg-ts-epoch a)
                            (Msg-ts-epoch b)))))
 
-(: paths->peers (-> (Listof String) (Setof Peer)))
+(: paths->peers (-> (Listof String) (Listof Peer)))
 (define (paths->peers paths)
   (let* ([paths (match paths
                   ['()
-                   (let ([peer-refs-file (build-path tt-home-dir "peers")])
+                   (let ([peer-refs-file (build-path tt-home-dir "following.txt")])
                      (log-debug
                        "No peer ref file paths provided, defaulting to ~v"
                        (path->string peer-refs-file))
@@ -711,8 +771,8 @@
                   [paths
                     (log-debug "Peer ref file paths provided: ~v" paths)
                     (map string->path paths)])]
-         [peers (apply peers-union (map file->peers paths))])
-    (log-info "Read-in ~a peers." (set-count peers))
+         [peers (apply peers-merge (map file->peers paths))])
+    (log-info "Read-in ~a peers." (length peers))
     peers))
 
 (: cache-filename->peer (-> Path-String (Option Peer)))
@@ -723,16 +783,28 @@
     [#f #f]
     [url (Peer nick url url-str #f)]))
 
-(: peers-cached (-> (Setof Peer)))
+(: peers-cached (-> (Listof Peer)))
 (define (peers-cached)
   ; TODO Expire cache?
-  (make-immutable-peers
-    (filter-map cache-filename->peer
-                (directory-list cache-object-dir))))
+  (filter-map cache-filename->peer (directory-list cache-object-dir)))
 
-(: peers-mentioned (-> (Listof Msg) (Setof Peer)))
+(: peers-mentioned (-> (Listof Msg) (Listof Peer)))
 (define (peers-mentioned msgs)
-  (make-immutable-peers (append* (map Msg-mentions msgs))))
+  (append* (map Msg-mentions msgs)))
+
+(: peers-filter-denied-domains (-> (Listof Peer) (Listof Peer)))
+(define (peers-filter-denied-domains peers)
+  (define deny-file (build-path tt-home-dir "domains-deny.txt"))
+  (define denied-hosts
+    (list->set (map string-trim (filter-comments (file->lines deny-file)))))
+  (define denied-domain-patterns
+    (set-map denied-hosts (λ (h) (pregexp (string-append "\\." h "$")))))
+  (filter
+    (λ (p)
+       (define host (url-host (Peer-uri p)))
+       (not (or (set-member? denied-hosts host)
+                (ormap (λ (d) (regexp-match? d host)) denied-domain-patterns))))
+    peers))
 
 (: log-writer-stop (-> Thread Void))
 (define (log-writer-stop log-writer)
@@ -758,49 +830,182 @@
     (current-logger logger)
     log-writer))
 
+(: msgs->nick-hist (-> (Listof Msg) Url-Nick-Hist))
+(define (msgs->nick-hist msgs)
+  (foldl
+    (λ (msg url->nick->hist)
+       (match-define (Msg curr _ from _ mentions) msg)
+       (foldl
+         (λ (peer url->nick->hist)
+            (match-define (Peer nick url _ _) peer)
+            (if nick
+                (hash-update url->nick->hist
+                             url
+                             (λ (nick->hist)
+                                (hash-update nick->hist
+                                             nick
+                                             (match-lambda
+                                               [(Hist freq prev)
+                                                (Hist (+ 1 freq) (max prev curr))])
+                                             (Hist 0 0)))
+                             (hash))
+                url->nick->hist))
+         url->nick->hist
+         (cons from mentions)))
+    (hash)
+    msgs))
+
+(: url-nick-hist->file (-> Url-Nick-Hist Path-String Void))
+(define (url-nick-hist->file unh filepath)
+  (define out (open-output-file filepath #:exists 'replace))
+  (for-each
+    (match-lambda
+      [(cons url nick->hist)
+       (displayln (url->string url) out)
+       (for-each (match-lambda
+                   [(cons nick (Hist freq last))
+                    (displayln (format "    ~a ~a ~a" nick freq last) out)])
+                 (sort (hash->list nick->hist)
+                       (match-lambda**
+                         [((cons _ (Hist a _)) (cons _ (Hist b _)))
+                          (> a b)])))])
+    (sort
+      (hash->list unh)
+      (λ (a b) (string<? (url-host (car a))
+                         (url-host (car b))))))
+  (close-output-port out))
+
+(: url-nick-hist->dir (-> Url-Nick-Hist Path-String Void))
+(define (url-nick-hist->dir unh dirpath)
+  (hash-for-each
+    unh
+    (λ (url nick->hist)
+       (define filename (string-append (uri-encode (url->string url)) ".txt"))
+       (define filepath (build-path dirpath filename))
+       (make-parent-directory* filepath)
+       (display-lines-to-file
+         (map (match-lambda
+                [(cons nick (Hist freq last))
+                 (format "~a ~a ~a" nick freq last)])
+              (sort (hash->list nick->hist)
+                    (match-lambda**
+                      [((cons _ (Hist a _)) (cons _ (Hist b _)))
+                       (> a b)])))
+         filepath
+         #:exists 'replace))))
+
+(: update-nicks-history-files (-> Url-Nick-Hist Void))
+(define (update-nicks-history-files unh)
+  (define nicks-dir (build-path tt-home-dir "nicks"))
+  (url-nick-hist->file unh (build-path nicks-dir "seen.txt"))
+  (url-nick-hist->dir  unh (build-path nicks-dir "seen")))
+
+(: url-nick-hist-most-by (-> Url-Nick-Hist Url (-> Hist Nonnegative-Integer) (Option String)))
+(define (url-nick-hist-most-by url->nick->hist url by)
+  (match (hash-ref url->nick->hist url #f)
+    [#f #f]
+    [nick->hist
+      (match (sort (hash->list nick->hist)
+                   (λ (a b) (> (by (cdr a))
+                               (by (cdr b)))))
+        ['() #f]
+        [(cons (cons nick _) _) nick])]))
+
+(: url-nick-hist-latest (-> Url-Nick-Hist Url (Option String)))
+(define (url-nick-hist-latest unh url)
+  (url-nick-hist-most-by unh url Hist-last))
+
+(: url-nick-hist-common (-> Url-Nick-Hist Url (Option String)))
+(define (url-nick-hist-common unh url)
+  (url-nick-hist-most-by unh url Hist-freq))
+
+(: peers-update-nick-to-common (-> Url-Nick-Hist (Listof Peer) (Listof Peer)))
+(define (peers-update-nick-to-common unh peers)
+  (map
+    (λ (p)
+       (match (url-nick-hist-common unh (Peer-uri p))
+         [#f p]
+         [n (struct-copy Peer p [nick n])]))
+    peers))
+
+(module+ test
+  (let* ([url-str  "http://foo"]
+         [url      (string->url url-str)]
+         [nick1    "a"]
+         [nick2    "b"]
+         [nick3    "c"]
+         [ts-str-1 "2021-11-29T23:29:08-0500"]
+         [ts-str-2 "2021-11-29T23:30:00-0500"]
+         [ts-1     (rfc3339->epoch ts-str-1)]
+         [ts-2     (rfc3339->epoch ts-str-2)]
+         [msgs
+           (map (match-lambda
+                  [(cons ts-str nick)
+                   (str->msg (str->peer "test http://test")
+                             (string-append ts-str "	Hi @<" nick " " url-str ">"))])
+                (list (cons ts-str-2 nick1)
+                      (cons ts-str-1 nick2)
+                      (cons ts-str-1 nick2)
+                      (cons ts-str-1 nick3)
+                      (cons ts-str-1 nick3)
+                      (cons ts-str-1 nick3)))]
+         [hist
+           (msgs->nick-hist msgs)])
+    (check-equal? (hash-ref (hash-ref hist url) nick1) (Hist 1 ts-2))
+    (check-equal? (hash-ref (hash-ref hist url) nick2) (Hist 2 ts-1))
+    (check-equal? (hash-ref (hash-ref hist url) nick3) (Hist 3 ts-1))
+    (check-equal? (url-nick-hist-common hist url) nick3)
+    (check-equal? (url-nick-hist-latest hist url) nick1)))
+
 (: crawl (-> Void))
 (define (crawl)
+  ; TODO Test the non-io parts of crawling
   (let* ([peers-all-file
-           (build-path tt-home-dir "peers-all")]
+           (build-path pub-peers-dir "all.txt")]
          [peers-mentioned-file
-           (build-path tt-home-dir "peers-mentioned")]
+           (build-path pub-peers-dir "mentioned.txt")]
          [peers-parsed-file
-           (build-path tt-home-dir "peers-parsed")]
+           (build-path pub-peers-dir "downloaded-and-parsed.txt")]
          [peers-cached-file
-           (build-path tt-home-dir "peers-cached")]
+           (build-path pub-peers-dir "downloaded.txt")]
          [peers-cached
            (peers-cached)]
          [cached-timeline
            (peers->timeline peers-cached)]
+         [url-nick-hist
+           (msgs->nick-hist cached-timeline)]
          [peers-mentioned-curr
            (peers-mentioned cached-timeline)]
          [peers-mentioned-prev
            (file->peers peers-mentioned-file)]
-         [peers-mentioned
-           (peers-union peers-mentioned-prev
-                        peers-mentioned-curr)]
          [peers-all-prev
            (file->peers peers-all-file)]
+         [peers-mentioned
+           (peers-merge peers-mentioned-prev
+                        peers-mentioned-curr)]
          [peers-all
-           (peers-union peers-mentioned
-                        peers-all-prev
-                        peers-cached)]
+           (peers-update-nick-to-common
+             url-nick-hist
+             (peers-merge peers-mentioned
+                          peers-all-prev
+                          peers-cached))]
          [peers-discovered
-           (set-subtract peers-all
-                         peers-all-prev)]
+           (set->list (set-subtract (make-immutable-peers peers-all)
+                                    (make-immutable-peers peers-all-prev)))]
          [peers-parsed
-           (for/set ([p peers-all] #:when (> (length (peer->msgs p)) 0)) p)])
+           (filter (λ (p) (> (length (peer->msgs p)) 0)) peers-all)])
     ; TODO Deeper de-duping
-    (log-info "Known peers cached ~a" (set-count peers-cached))
-    (log-info "Known peers mentioned: ~a" (set-count peers-mentioned))
-    (log-info "Known peers parsed ~a" (set-count peers-parsed))
-    (log-info "Known peers total: ~a" (set-count peers-all))
+    (log-info "Known peers cached ~a" (length peers-cached))
+    (log-info "Known peers mentioned: ~a" (length peers-mentioned))
+    (log-info "Known peers parsed ~a" (length peers-parsed))
+    (log-info "Known peers total: ~a" (length peers-all))
     (log-info "Discovered ~a new peers:~n~a"
-              (set-count peers-discovered)
+              (length peers-discovered)
               (pretty-format (map
                                (match-lambda
                                  [(Peer n _ u c) (list n u c)])
-                               (set->list peers-discovered))))
+                               peers-discovered)))
+    (update-nicks-history-files url-nick-hist)
     (peers->file peers-cached
                  peers-cached-file)
     (peers->file peers-mentioned
@@ -831,20 +1036,21 @@
 
 (: download (-> (Listof String) Positive-Integer Positive-Float Void))
 (define (download file-paths num-workers timeout)
-  (let ([peers (paths->peers file-paths)])
+  (let* ([peers-given (paths->peers file-paths)]
+         [peers-kept (peers-filter-denied-domains peers-given)]
+         [peers-denied (set-subtract peers-given peers-kept)])
+    (log-info "Denied ~a peers" (length peers-denied))
     (define-values (_res _cpu real-ms _gc)
-      (time-apply timeline-download (list num-workers timeout peers)))
+      (time-apply timeline-download (list num-workers timeout peers-kept)))
     (log-info "Downloaded timelines from ~a peers in ~a seconds."
-              (set-count peers)
+              (length peers-kept)
               (/ real-ms 1000.0))))
 
 (: dispatch (-> String Void))
 (define (dispatch command)
   (match command
     [(or "d" "download")
-     ; Initially, 15 was fastest out of the tried: 1, 5, 10, 20.  Then I
-     ; started noticing significant slowdowns. Reducing to 5 seems to help.
-     (let ([num-workers 5]
+     (let ([num-workers 20] ; 20 was fastest out of the tried: 1, 5, 10, 20, 25, 30.
            [timeout     10.0])
        (command-line
          #:program "tt download"
@@ -915,6 +1121,7 @@
       #:args (command . args)
       (define log-writer (log-writer-start log-level))
       (current-command-line-arguments (list->vector args))
+      (set-user-agent-str (build-path tt-home-dir "user.txt"))
       ; TODO dispatch should return status with which we should exit after cleanups
       (dispatch command)
       (log-writer-stop log-writer))))