Add experimental get|set_url capability

frontend/src/App.tsx

@@ -260,6 +260,7 @@ export class App extends PureComponent<Props, State> {
         uploadReportProgress: (progress: string | number) =>
           this.handleUploadReportProgress(progress),
         reportUploaded: (url: string) => this.handleReportUploaded(url),
+        newUrl: (new_url: string) => this.handleNewUrlChange(new_url),
       })
     } catch (err) {
       logError(err)
@@ -339,6 +340,11 @@ export class App extends PureComponent<Props, State> {
     })
 
     this.handleSessionStateChanged(sessionState)
+
+    // send current URL to server
+    const backMsg = new BackMsg({ urlInfo: window.location.href })
+    backMsg.type = "urlInfo"
+    this.sendBackMsg(backMsg)
   }
 
   /**
@@ -454,6 +460,14 @@ export class App extends PureComponent<Props, State> {
     }
   }
 
+  /**
+   * Handler for ForwardMsg.newUrl messages
+   * @param newUrl string
+   */
+  handleNewUrlChange = (newUrl: string): void => {
+    window.history.pushState({}, "", newUrl ? newUrl : "/")
+  }
+
   /**
    * Handler for ForwardMsg.reportFinished messages
    * @param status the ReportFinishedStatus that the report finished with

lib/streamlit/ReportSession.py

@@ -103,6 +103,8 @@ def __init__(self, ioloop, script_path, command_line, uploaded_file_manager):
         self._script_request_queue = ScriptRequestQueue()
 
         self._scriptrunner = None
+        self.base_url = None
+        self.query_url = ""
 
         LOGGER.debug("ReportSession initialized (id=%s)", self.id)
 

lib/streamlit/__init__.py

@@ -102,6 +102,8 @@
 from streamlit.DeltaGenerator import DeltaGenerator as _DeltaGenerator
 from streamlit.ReportThread import add_report_ctx as _add_report_ctx
 from streamlit.ReportThread import get_report_ctx as _get_report_ctx
+from streamlit.server.Server import Server
+from streamlit.proto.ForwardMsg_pb2 import ForwardMsg
 from streamlit.errors import StreamlitAPIException
 from streamlit.proto import BlockPath_pb2 as _BlockPath_pb2
 from streamlit.util import functools_wraps as _functools_wraps
@@ -580,6 +582,38 @@ def _transparent_write(*args):
     return args
 
 
+def _get_url():
+    """
+    this should just return the url that the current session is running on
+    """
+    ctx = _get_report_ctx()
+    session_infos = Server.get_current()._session_info_by_id
+    for socket_handler, session_info in session_infos.items():
+        if session_info.session.enqueue == ctx.enqueue:
+            session = session_info.session
+            if not session.base_url:
+                raise StreamlitAPIException(
+                    "Something is wrong when fetching current browser URL. Please try again."
+                )
+            else:
+                return session.base_url + str(session.query_url)
+
+
+def _set_url(url_to_set):
+    """
+    this should just append/replace url_to_set to the current session's existing hostname.
+    """
+    ctx = _get_report_ctx()
+    session_infos = Server.get_current()._session_info_by_id
+    for socket_handler, session_info in session_infos.items():
+        if session_info.session.enqueue == ctx.enqueue:
+            session = session_info.session
+            newUrlMsg = ForwardMsg()
+            newUrlMsg.new_url = url_to_set
+            session._report.enqueue(newUrlMsg)
+            session.query_url = url_to_set
+
+
 # We want to show a warning when the user runs a Streamlit script without
 # 'streamlit run', but we need to make sure the warning appears only once no
 # matter how many times __init__ gets loaded.
@@ -693,6 +727,9 @@ class _ExperimentalNamespace(object):
     # Add experimental features here. For example:
     # foo = _foo
     show = _show
+    get_url = _get_url
+    set_url = _set_url
+
 
 
 beta = _BetaNamespace

lib/streamlit/server/Server.py

@@ -618,6 +618,9 @@ def on_message(self, payload):
                         "Client tried to close connection when "
                         "not in development mode"
                     )
+            elif msg_type == "url_info":
+                self._session.base_url = msg.url_info
+                LOGGER.debug("Successfully set base URL :\n%s", msg.url_info)
             else:
                 LOGGER.warning('No handler for "%s"', msg_type)
 

proto/streamlit/proto/BackMsg.proto

@@ -49,5 +49,8 @@ message BackMsg {
 
     // Set to true to ask the server to close the connection
     bool close_connection = 10;
+
+    // Request to pass current URL to backend
+    string url_info = 11;
   }
 }

proto/streamlit/proto/ForwardMsg.proto

@@ -72,6 +72,9 @@ message ForwardMsg {
     // for this one. If the client does not have the referenced message
     // in its cache, it can retrieve it from the server.
     string ref_hash = 11;
+
+    // new_url for curious users to set params
+    string new_url = 12;
   }
 }