pyscript · FabioRosado · Jan 4, 2023 · Jan 5, 2023 · hoodmane · May 19, 2023
diff --git a/pyscriptjs/src/main.ts b/pyscriptjs/src/main.ts
@@ -16,6 +16,7 @@ import { type Stdio, StdioMultiplexer, DEFAULT_STDIO } from './stdio';
 import { PyTerminalPlugin } from './plugins/pyterminal';
 import { SplashscreenPlugin } from './plugins/splashscreen';
 import { ImportmapPlugin } from './plugins/importmap';
+import { AutomaticImportPlugin } from './plugins/automaticImport';
 // eslint-disable-next-line
 // @ts-ignore
 import pyscript from './python/pyscript.py';
@@ -66,7 +67,12 @@ export class PyScriptApp {
     constructor() {
         // initialize the builtin plugins
         this.plugins = new PluginManager();
-        this.plugins.add(new SplashscreenPlugin(), new PyTerminalPlugin(this), new ImportmapPlugin());
+        this.plugins.add(
+            new SplashscreenPlugin(),
+            new PyTerminalPlugin(this),
+            new ImportmapPlugin(),
+            new AutomaticImportPlugin(),
+        );
 
         this._stdioMultiplexer = new StdioMultiplexer();
         this._stdioMultiplexer.addListener(DEFAULT_STDIO);

diff --git a/pyscriptjs/src/plugins/automaticImport.ts b/pyscriptjs/src/plugins/automaticImport.ts
@@ -0,0 +1,107 @@
+import type { AppConfig } from '../pyconfig';
+import { robustFetch } from '../fetch';
+import { Plugin } from '../plugin';
+import { getLogger } from '../logger';
+
+const logger = getLogger('automatic-import-plugin');
+
+export class AutomaticImportPlugin extends Plugin {
+    pyscriptTag = document.querySelector('py-script');
+
+    /**
+     * Trim whitespace from the beginning and end of a string.
+     * The text that we are getting has new lines and possibly
+     * whitespace at the beginning and end of the line. Since
+     * we want to match only import statements, we need to trim
+     * the whitespace on each line, join them together and then
+     * match each beginning of the line so the regex rule will
+     * only match what we perceive as import statements.
+     *
+     * NOTE: This is not a perfect solution and I'm a bit worried
+     * about the performance of this. I'm sure there is a better
+     * way to do this.
+     *
+     * @param text - The text to trim
+     */
+    _trimWhiteSpace(text: string): string {
+        const lines = text.split('\n');
+        return lines.map(line => line.trim()).join('\n');
+    }
+    /**
+     *
+     * Use regex magic to capture import statements and add the
+     * dependency(s) to the packages list in the config.
+     *
+     * @param text - The text to search for import statements
+     * @param config - The config object to add the dependencies to
+     *
+     */
+    _addImportToPackagesList(text: string, config: AppConfig) {
+        // Regex encantation to capture the imported dependency into a
+        // named group called "dependency". The rule will match any text
+        // that contains 'import' or 'from' at the beginning of the line
+        // or '\nimport', '\nfrom' which is the case when we invoke _trimWhiteSpace
+        const importRegexRule = /^(?:\\n)?(?:import|from)\s+(?<dependency>[a-zA-Z0-9_]+)?/gm;
-        const importRegexRule = /^(?:\\n)?(?:import|from)\s+(?<dependency>[a-zA-Z0-9_]+)?/gm;
+        const importRegexRule = /^(?:\\n)?\s*(?:import|from)\s+(?<dependency>[a-zA-Z0-9_]+)?/gm;
-        const importRegexRule = /^(?:\\n)?(?:import|from)\s+(?<dependency>[a-zA-Z0-9_]+)?/gm;
+        const importRegexRule = /^(?:\\n)?\s*(?:import|from)\s+(?<dependency>[a-zA-Z0-9_]+)?/gm;
+
+        text = this._trimWhiteSpace(text);
+
+        const matches = text.matchAll(importRegexRule);
+        // Regex matches full match and groups, let's just push the group.
+        for (const match of matches) {
+            const dependency = match.groups.dependency;
+            if (dependency) {
+                logger.info(`Found import statement for ${dependency}, adding to packages list.`);
+                config.packages.push(dependency);
+            }
+        }
+    }
+
+    /**
+     *
+     * In this initial lifecycle hook, we will look for any imports
+     * in the <py-script> tag inner HTML and add them to the packages list.
+     *
+     * We are skipping looking into the src attribute to not delay the
+     * preliminary initialization phase.
+     *
+     */
+    configure(config: AppConfig) {
+        if (config.autoImports ?? true) {
+            // config.packages should already be a list, but
+            // let's be defensive just in case.
+            if (!config.packages) {
+                config.packages = [];
+            }
+
+            this._addImportToPackagesList(this.pyscriptTag.innerHTML, config);
+        }
+    }
+
+    /**
+     * In this lifecycle hook, we will to see if the user has specified a
+     * src attribute in the <py-script> tag and fetch the script if so. Then
+     * we will look for any imports in the fetched script and add them to the
+     * packages list.
+     *
+     * NOTE: If we are fetching the file from a URL and not from the local file
+     * system, this will delay the download of the python interpreter. Perhaps
+     * we should throw an error if the src attribute is a URL?
+     *
+     */
+    beforeLaunch(config: AppConfig) {
+        if (config.autoImports ?? true) {
+            const srcAttribute = this.pyscriptTag.getAttribute('src');
+            if (srcAttribute) {
+                logger.info(`Found src attribute in <py-script> tag, fetching ${srcAttribute}...`);
+                robustFetch(srcAttribute)
+                    .then(response => response.text())
+                    .then(text => {
+                        this._addImportToPackagesList(text, config);
+                    })
+                    .catch(error => {
+                        logger.error(`Failed to fetch ${srcAttribute}: ${(error as Error).message}`);
+                    });
+            }
+        }
+    }
+}
diff --git a/pyscriptjs/tests/integration/test_assets/automatic_import.py b/pyscriptjs/tests/integration/test_assets/automatic_import.py
@@ -0,0 +1,5 @@
+import numpy as np
+import pandas as pd
+
+print(np.__version__)
+print(pd.__version__)
diff --git a/pyscriptjs/tests/integration/test_plugins.py b/pyscriptjs/tests/integration/test_plugins.py
@@ -1,3 +1,5 @@
+import re
+
 from .support import PyScriptTest
 
 # Source code of a simple plugin that creates a Custom Element for testing purposes
@@ -186,3 +188,108 @@ def test_no_plugin_attribute_error(self):
         )
         # EXPECT an error for the missing attribute
         assert error_msg in self.console.error.lines
+
+
+class TestCorePlugins(PyScriptTest):
+    def test_core_plugin_automatic_import(self):
+        """Test that packages get installed automatically"""
+        self.pyscript_run(
+            """
+            <py-script>
+                import numpy as np
+                print(np.__version__)
+            </py-script>
+            """
+        )
+
+        py_terminal = self.page.locator("py-terminal")
+        assert re.match(r"\d+.\d+.\d+", py_terminal.inner_text())
+
+    def test_core_plugin_automatic_import_from(self):
+        """Test that packages get installed automatically"""
+        self.pyscript_run(
+            """
+            <py-script>
+                from numpy import __version__ as np_version
+                print(np_version)
+            </py-script>
+            """
+        )
+
+        py_terminal = self.page.locator("py-terminal")
+        assert re.match(r"\d+.\d+.\d+", py_terminal.inner_text())
+
+    def test_core_plugin_automatic_multiple_imports(self):
+        """Test that packages get installed automatically"""
+
+        self.pyscript_run(
+            """
+            <py-script>
+                import numpy as np
+                from pandas import __version__ as pandas_version
+                print(np.__version__)
+                print(pandas_version)
+            </py-script>
+            """
+        )
+
+        py_terminal = self.page.locator("py-terminal")
+        assert re.match(r"\d+.\d+.\d+\n\d+.\d+.\d+", py_terminal.inner_text())
+
+    def test_core_plugin_automatic_import_python_file(self):
+        """Test that packages get installed automatically"""
+        py_file = (
+            "import numpy as np\n"
+            "from pandas import __version__ as pandas_version\n"
+            "\n"
+            "print(np.__version__)\n"
+            "print(pandas_version)\n"
+        )
+
+        self.writefile("automatic_import.py", py_file)
+        self.pyscript_run(
+            """
+            <py-script src="automatic_import.py">
+            </py-script>
+            """
+        )
+
+        py_terminal = self.page.locator("py-terminal")
+        assert re.match(r"\d+.\d+.\d+\n\d+.\d+.\d+", py_terminal.inner_text())
+
+    def test_core_plugin_automatic_import_disabled(self):
+        """Test that packages get installed automatically"""
+        self.pyscript_run(
+            """
+            <py-config>
+                autoImports = false
+            </py-config>
+            <py-script>
+                from numpy import __version__ as np_version
+                print(np._version)
+            </py-script>
+            """,
+            wait_for_pyscript=False,
+        )
+
+        alert_banner = self.page.locator(".py-error")
+        assert (
+            "ModuleNotFoundError: No module named 'numpy'" in alert_banner.inner_text()
+        )
+
+    def test_core_plugin_automatic_import_doesnt_match_text(self):
+        """Test that packages get installed automatically"""
+        self.pyscript_run(
+            """
+            <py-script>
+                from numpy import __version__ as np_version
+                print(np_version)
+
+                def test_import_regex_logic():
+                    "from docstrings?"
+                    print("import my packages")
+            </py-script>
+            """
+        )
+        py_terminal = self.page.locator("py-terminal")
+        assert re.match(r"\d+.\d+.\d+", py_terminal.inner_text())