cache-control volflag; closes #964

README.md

@@ -1782,6 +1782,8 @@ notes:
 * `:c,magic` enables filetype detection for nameless uploads, same as `--magic`
   * needs https://pypi.org/project/python-magic/ `python3 -m pip install --user -U python-magic`
   * on windows grab this instead `python3 -m pip install --user -U python-magic-bin`
+* `cachectl` changes how webbrowser will cache responses (the `Cache-Control` response-header); default is `no-cache` which will prevent repeated downloading of the same file unless necessary (browser will ask copyparty if the file has changed)
+  * adding `?cache` to a link will override this with "fully cache this for 69 seconds"; `?cache=321` is 321 seconds, and `?cache=i` is 7 days
 
 
 ## database location

copyparty/__main__.py

@@ -1281,6 +1281,7 @@ def add_network(ap):
     ap2.add_argument("--xff-src", metavar="CIDR", type=u, default="127.0.0.0/8, ::1/128", help="list of trusted reverse-proxy CIDRs (comma-separated); only accept the real-ip header (\033[33m--xff-hdr\033[0m) and IdP headers if the incoming connection is from an IP within either of these subnets. Specify [\033[32mlan\033[0m] to allow all LAN / private / non-internet IPs. Can be disabled with [\033[32many\033[0m] if you are behind cloudflare (or similar) and are using \033[32m--xff-hdr=cf-connecting-ip\033[0m (or similar)")
     ap2.add_argument("--ipa", metavar="CIDR", type=u, default="", help="only accept connections from IP-addresses inside \033[33mCIDR\033[0m (comma-separated); examples: [\033[32mlan\033[0m] or [\033[32m10.89.0.0/16, 192.168.33.0/24\033[0m]")
     ap2.add_argument("--rp-loc", metavar="PATH", type=u, default="", help="if reverse-proxying on a location instead of a dedicated domain/subdomain, provide the base location here; example: [\033[32m/foo/bar\033[0m]")
+    ap2.add_argument("--cachectl", metavar="TXT", default="no-cache", help="default-value of the 'Cache-Control' response-header (controls caching in webbrowsers). Default prevents repeated downloading of the same file unless necessary (browser will ask copyparty if the file has changed). Examples: [\033[32mmax-age=604869\033[0m] will cache for 7 days, [\033[32mno-store, max-age=0\033[0m] will always redownload. (volflag=cachectl)")
     ap2.add_argument("--http-no-tcp", action="store_true", help="do not listen on TCP/IP for http/https; only listen on unix-domain-sockets")
     if ANYWIN:
         ap2.add_argument("--reuseaddr", action="store_true", help="set reuseaddr on listening sockets on windows; allows rapid restart of copyparty at the expense of being able to accidentally start multiple instances")

copyparty/authsrv.py

@@ -1054,6 +1054,7 @@ class AuthSrv(object):
         self.is_lxc = args.c == ["/z/initcfg"]
 
         self._vf0b = {
+            "cachectl": self.args.cachectl,
             "tcolor": self.args.tcolor,
             "du_iwho": self.args.du_iwho,
             "shr_who": self.args.shr_who if self.args.shr else "no",

copyparty/cfg.py

@@ -95,6 +95,7 @@ def vf_vmap() -> dict[str, str]:
     }
     for k in (
         "bup_ck",
+        "cachectl",
         "casechk",
         "chmod_d",
         "chmod_f",
@@ -419,6 +420,7 @@ flagcats = {
         "zipmaxt=no": "reply with 'no' if download-as-zip exceeds max",
         "zipmaxu": "zip-size-limit does not apply to authenticated users",
         "nopipe": "disable race-the-beam (download unfinished uploads)",
+        "cachectl=no-cache": "controls caching in webbrowsers",
         "mv_retry": "ms-windows: timeout for renaming busy files",
         "rm_retry": "ms-windows: timeout for deleting busy files",
         "davauth": "ask webdav clients to login for all folders",

copyparty/httpcli.py

@@ -149,8 +149,6 @@ _ = (argparse, threading)
 
 USED4SEC = {"usedforsecurity": False} if sys.version_info > (3, 9) else {}
 
-NO_CACHE = {"Cache-Control": "no-cache"}
-
 ALL_COOKIES = "k304 no304 js idxh dots cppwd cppws".split()
 
 BADXFF = " due to dangerous misconfiguration (the http-header specified by --xff-hdr was received from an untrusted reverse-proxy)"
@@ -973,7 +971,7 @@ class HttpCli(object):
     def permit_caching(self) -> None:
         cache = self.uparam.get("cache")
         if cache is None:
-            self.out_headers.update(NO_CACHE)
+            self.out_headers["Cache-Control"] = self.vn.flags["cachectl"]
             return
 
         n = 69 if not cache else 604869 if cache == "i" else int(cache)
@@ -5159,7 +5157,7 @@ class HttpCli(object):
         file_ts = int(max(ts_md, self.E.t0))
         file_lastmod, do_send, _ = self._chk_lastmod(file_ts)
         self.out_headers["Last-Modified"] = file_lastmod
-        self.out_headers.update(NO_CACHE)
+        self.out_headers["Cache-Control"] = "no-cache"
         status = 200 if do_send else 304
 
         arg_base = "?"

tests/util.py

@@ -167,7 +167,7 @@ class Cfg(Namespace):
         ex = "ah_alg bname chdir chmod_f chpw_db doctitle df epilogues exit favico ipa html_head html_head_d html_head_s idp_login idp_logout lg_sba lg_sbf log_date log_fk md_sba md_sbf name og_desc og_site og_th og_title og_title_a og_title_v og_title_i opds_exts preadmes prologues readmes shr tcolor textfiles txt_eol ufavico ufavico_h unlist vname xff_src zipmaxt R RS SR"
         ka.update(**{k: "" for k in ex.split()})
 
-        ex = "ban_403 ban_404 ban_422 ban_pw ban_pwc ban_url dont_ban rss_fmt_d rss_fmt_t spinner"
+        ex = "ban_403 ban_404 ban_422 ban_pw ban_pwc ban_url dont_ban cachectl rss_fmt_d rss_fmt_t spinner"
         ka.update(**{k: "no" for k in ex.split()})
 
         ex = "ext_th grp idp_h_usr idp_hm_usr ipr on403 on404 qr_file xac xad xar xau xban xbc xbd xbr xbu xiu xm"