Implement config.baseUrlPath (streamlit#454)

* Implement server.baseUrlPath config option.

* Improve st.image pydoc.

* Improve baseUrlPath support for trailing slash

* Implement JS tests

* Add more JS tests

* Fix tests

* Run pyformat on all files

docs/conf.py

@@ -91,9 +91,7 @@
 # further.  For a list of options available for each theme, see the
 # documentation.
 
-html_theme_options = {
-    "analytics_id": "UA-122023594-3",
-}
+html_theme_options = {"analytics_id": "UA-122023594-3"}
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,

e2e/scripts/sidebar.py

@@ -23,5 +23,5 @@
 w2 = st.sidebar.date_input("Label 2", datetime(2019, 7, 6, 21, 15))
 st.write("Value 2:", w2)
 
-x = st.sidebar.text('overwrite me')
-x.text('overwritten')
+x = st.sidebar.text("overwrite me")
+x.text("overwritten")

e2e/scripts/vega_lite_chart.py

@@ -87,8 +87,8 @@
     }
 )
 
-#st.write("Putting the `df` inside the spec, as inline `data` (different notation):")
-#This fails now, but not a big deal. It's a weird notation.
+# st.write("Putting the `df` inside the spec, as inline `data` (different notation):")
+# This fails now, but not a big deal. It's a weird notation.
 
 # st.vega_lite_chart({
 #     'data': {'values': df},

frontend/src/lib/ConnectionManager.ts

@@ -177,13 +177,16 @@ export class ConnectionManager {
       internalServerIP,
       externalServerIP,
       serverPort,
+      serverBasePath,
     } = manifest
 
+    const parts = { port: serverPort, basePath: serverBasePath }
+
     const baseUriPartsList = configuredServerAddress
-      ? [{ host: configuredServerAddress, port: serverPort }]
+      ? [{ ...parts, host: configuredServerAddress }]
       : [
-          { host: externalServerIP, port: serverPort },
-          { host: internalServerIP, port: serverPort },
+          { ...parts, host: externalServerIP },
+          { ...parts, host: internalServerIP },
         ]
 
     return new WebsocketConnection({

frontend/src/lib/ForwardMessageCache.test.ts

@@ -20,7 +20,11 @@ import fetchMock from "fetch-mock"
 import { ForwardMsgCache } from "lib/ForwardMessageCache"
 import { buildHttpUri } from "lib/UriUtil"
 
-const MOCK_SERVER_URI = { host: "streamlit.mock", port: 80 }
+const MOCK_SERVER_URI = {
+  host: "streamlit.mock",
+  port: 80,
+  basePath: "",
+}
 
 interface MockCache {
   cache: ForwardMsgCache

frontend/src/lib/UriUtil.test.ts

@@ -0,0 +1,153 @@
+/**
+ * @license
+ * Copyright 2018-2019 Streamlit Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { buildHttpUri, buildWsUri, getWindowBaseUriParts } from "./UriUtil"
+
+const location = {}
+
+global.window = Object.create(window)
+Object.defineProperty(window, "location", { value: location })
+
+test("gets all window URI parts", () => {
+  location.hostname = "the_host"
+  location.port = "9988"
+  location.pathname = "foo"
+
+  const parts = getWindowBaseUriParts()
+  expect(parts).toStrictEqual({
+    host: "the_host",
+    port: 9988,
+    basePath: "foo",
+  })
+})
+
+test("gets window URI parts without basePath", () => {
+  location.hostname = "the_host"
+  location.port = "9988"
+  location.pathname = ""
+
+  const parts = getWindowBaseUriParts()
+  expect(parts).toStrictEqual({
+    host: "the_host",
+    port: 9988,
+    basePath: "",
+  })
+})
+
+test("gets window URI parts with long basePath", () => {
+  location.hostname = "the_host"
+  location.port = "9988"
+  location.pathname = "/foo/bar"
+
+  const parts = getWindowBaseUriParts()
+  expect(parts).toStrictEqual({
+    host: "the_host",
+    port: 9988,
+    basePath: "foo/bar",
+  })
+})
+
+test("gets window URI parts with weird basePath", () => {
+  location.hostname = "the_host"
+  location.port = "9988"
+  location.pathname = "///foo/bar//"
+
+  const parts = getWindowBaseUriParts()
+  expect(parts).toStrictEqual({
+    host: "the_host",
+    port: 9988,
+    basePath: "foo/bar",
+  })
+})
+
+test("builds HTTP URI correctly", () => {
+  location.href = "http://something"
+  const uri = buildHttpUri(
+    {
+      host: "the_host",
+      port: 9988,
+      basePath: "foo/bar",
+    },
+    "baz"
+  )
+  expect(uri).toBe("http://the_host:9988/foo/bar/baz")
+})
+
+test("builds HTTPS URI correctly", () => {
+  location.href = "https://something"
+  const uri = buildHttpUri(
+    {
+      host: "the_host",
+      port: 9988,
+      basePath: "foo/bar",
+    },
+    "baz"
+  )
+  expect(uri).toBe("https://the_host:9988/foo/bar/baz")
+})
+
+test("builds HTTP URI with no base path", () => {
+  location.href = "http://something"
+  const uri = buildHttpUri(
+    {
+      host: "the_host",
+      port: 9988,
+      basePath: "",
+    },
+    "baz"
+  )
+  expect(uri).toBe("http://the_host:9988/baz")
+})
+
+test("builds WS URI correctly", () => {
+  location.href = "http://something"
+  const uri = buildWsUri(
+    {
+      host: "the_host",
+      port: 9988,
+      basePath: "foo/bar",
+    },
+    "baz"
+  )
+  expect(uri).toBe("ws://the_host:9988/foo/bar/baz")
+})
+
+test("builds WSS URI correctly", () => {
+  location.href = "https://something"
+  const uri = buildWsUri(
+    {
+      host: "the_host",
+      port: 9988,
+      basePath: "foo/bar",
+    },
+    "baz"
+  )
+  expect(uri).toBe("wss://the_host:9988/foo/bar/baz")
+})
+
+test("builds WS URI with no base path", () => {
+  location.href = "http://something"
+  const uri = buildWsUri(
+    {
+      host: "the_host",
+      port: 9988,
+      basePath: "",
+    },
+    "baz"
+  )
+  expect(uri).toBe("ws://the_host:9988/baz")
+})

frontend/src/lib/UriUtil.ts

@@ -23,8 +23,12 @@ import { IS_DEV_ENV, WEBSOCKET_PORT_DEV } from "lib/baseconsts"
 export interface BaseUriParts {
   host: string
   port: number
+  basePath: string
 }
 
+const FINAL_SLASH_RE = /\/+$/
+const INITIAL_SLASH_RE = /^\/+/
+
 /**
  * Return the BaseUriParts for the global window
  */
@@ -33,36 +37,56 @@ export function getWindowBaseUriParts(): BaseUriParts {
   // server's port 3000.
   // If changed, also change config.py
   const host = window.location.hostname
+
+  // prettier-ignore
   const port = IS_DEV_ENV
     ? WEBSOCKET_PORT_DEV
     : window.location.port
-    ? Number(window.location.port)
-    : isHttps()
-    ? 443
-    : 80
-  return { host, port }
+      ? Number(window.location.port)
+      : isHttps()
+        ? 443
+        : 80
+
+  const basePath = window.location.pathname
+    .replace(FINAL_SLASH_RE, "")
+    .replace(INITIAL_SLASH_RE, "")
+
+  return { host, port, basePath }
 }
 
 /**
  * Create a ws:// or wss:// URI for the given path.
  */
 export function buildWsUri(
-  { host, port }: BaseUriParts,
+  { host, port, basePath }: BaseUriParts,
   path: string
 ): string {
   const protocol = isHttps() ? "wss" : "ws"
-  return `${protocol}://${host}:${port}/${path}`
+  const fullPath = makePath(basePath, path)
+  return `${protocol}://${host}:${port}/${fullPath}`
 }
 
 /**
  * Create an HTTP URI for the given path.
  */
 export function buildHttpUri(
-  { host, port }: BaseUriParts,
+  { host, port, basePath }: BaseUriParts,
   path: string
 ): string {
   const protocol = isHttps() ? "https" : "http"
-  return `${protocol}://${host}:${port}/${path}`
+  const fullPath = makePath(basePath, path)
+  return `${protocol}://${host}:${port}/${fullPath}`
+}
+
+function makePath(basePath: string, subPath: string): string {
+  basePath = basePath.replace(FINAL_SLASH_RE, "").replace(INITIAL_SLASH_RE, "")
+  subPath = subPath.replace(FINAL_SLASH_RE, "").replace(INITIAL_SLASH_RE, "")
+
+  if (basePath.length === 0) {
+    return subPath
+  }
+
+  return `${basePath}/${subPath}`
 }
 
 /**

lib/streamlit/DeltaGenerator.py

@@ -1305,7 +1305,8 @@ def image(
             `image[:, :, 2]` is blue. For images coming from libraries like
             OpenCV you should set this to 'BGR', instead.
         format : 'JPEG' or 'PNG'
-            This parameter specifies the image format. Defaults to 'JPEG'.
+            This parameter specifies the image format to use when transferring
+            the image data. Defaults to 'JPEG'.
 
         Example
         -------

lib/streamlit/Report.py

@@ -51,7 +51,16 @@ def get_url(cls, host_ip):
             The URL.
         """
         port = _get_browser_address_bar_port()
-        return "http://%(host_ip)s:%(port)s" % {"host_ip": host_ip, "port": port}
+        base_path = config.get_option("server.baseUrlPath").strip("/")
+
+        if base_path:
+            base_path = "/" + base_path
+
+        return "http://%(host_ip)s:%(port)s%(base_path)s" % {
+            "host_ip": host_ip.strip("/"),
+            "port": port,
+            "base_path": base_path,
+        }
 
     def __init__(self, script_path, command_line):
         """Constructor.
@@ -243,6 +252,7 @@ def _build_manifest(
             # websocket port, not the web server port. (These are the same in
             # prod, but different in dev)
             manifest.server_port = config.get_option("browser.serverPort")
+            manifest.server_base_path = config.get_option("server.baseUrlPath")
         else:
             manifest.num_messages = num_messages
 

lib/streamlit/ReportSession.py

@@ -87,10 +87,10 @@ def __init__(self, ioloop, script_path, command_line):
 
         self._state = ReportSessionState.REPORT_NOT_RUNNING
 
-        self._main_dg = DeltaGenerator(
-            enqueue=self.enqueue, container=BlockPath.MAIN)
+        self._main_dg = DeltaGenerator(enqueue=self.enqueue, container=BlockPath.MAIN)
         self._sidebar_dg = DeltaGenerator(
-            enqueue=self.enqueue, container=BlockPath.SIDEBAR)
+            enqueue=self.enqueue, container=BlockPath.SIDEBAR
+        )
 
         self._widget_states = WidgetStates()
         self._local_sources_watcher = LocalSourcesWatcher(
@@ -526,6 +526,7 @@ def handle_save_request(self, ws):
             The report's websocket handler.
 
         """
+
         @tornado.gen.coroutine
         def progress(percent):
             progress_msg = ForwardMsg()

lib/streamlit/config.py

@@ -423,6 +423,16 @@ def _server_port():
     return 8501
 
 
+_create_option(
+    "server.baseUrlPath",
+    description="""
+        The base path for the URL where Streamlit should be served from.
+        """,
+    default_val="",
+    type_=str,
+)
+
+
 @_create_option("server.enableCORS", type_=bool)
 def _server_enable_cors():
     """Enables support for Cross-Origin Request Sharing, for added security.

lib/streamlit/hello/demos.py

@@ -221,11 +221,14 @@ def get_UN_data():
     try:
         df = get_UN_data()
     except urllib.error.URLError as e:
-        st.error("""
+        st.error(
+            """
             **This demo requires internet access.**
 
             Connection error: %s
-        """ % e.reason)
+        """
+            % e.reason
+        )
         return
 
     countries = st.multiselect(