Added startup scripts

Author: Alathreon

JShellAPI/GUIDE.MD

@@ -2,13 +2,15 @@
 ### Eval
 Everything works with sessions, the code is evaluated on a session which has a certain lifetime.
 ```
-POST   /eval/{id}     body=code   -> JShellResult
-POST   /eval          body=code   -> JShellResultWithId
-POST   /single-eval   body=code   -> JShellResult
+POST   /eval/{id}           body=code   -> JShellResult         params=startupScriptId:id
+POST   /eval                body=code   -> JShellResultWithId   params=startupScriptId:id
+POST   /single-eval         body=code   -> JShellResult         params=startupScriptId:id
 ```
 - The first one takes an id, create a session from this id, or use an existing session if this id already exists.
 - The second one creates a new session each time, with a random id, and so it returns the generated id, in order to be reused.
 - The third one creates a session that can only be used once, not only that, but this session is called a one-time session and has lower timeout.
+- the optional parameter startupScriptId may be added to specify the startup script id.
+
 #### Response
 In all three, a string containing code to be evaluated needs to be supplied, and a JShellResult will be returned containing the result :
 ```java
@@ -40,11 +42,14 @@ record JShellResultWithId(
 ```
 ### Other endpoints
 ```
-GET    /snippets/{id}  body=none   -> List<String>
-DELETE /{id}           body=none   -> none
+GET    /snippets/{id}       body=none   -> List<String>         params=includeStartupScript:boolean
+DELETE /{id}                body=none   -> none
+GET    /startup_script/{id} body=none   -> String
 ```
 - The first one will retrieve all snippets of a given session
 - The second one will forcibly delete the given session
+  - the optional parameter includeStartupScript may be supplied to indicate if the startup script should be returned, by default false
+- The third one will return the startup script for the corresponding startup script id
 ### Errors
 if a problem happens, by default a 5XX error will be thrown, except in those cases :
 - Given [id](#Identifiers) is invalid : 400 Bad Request.
@@ -74,6 +79,13 @@ The identifier must match the following regex :
 [a-zA-Z0-9][a-zA-Z0-9_.-]+
 ```
 A random identifier is simply a random uuid.
+### Startup script
+A startup script can be used, so it's easier to use jshell.
+They are special scripts that are automatically evaluated at the launch of a session, to change the startup script of a session, the session must be deleted.
+The startup scripts are the two first scripts of a session, the first being the imports, the second the rest of the startup script.
+The following startup scripts id can be used :
+- EMPTY : no startup script
+- CUSTOM_DEFAULT : contains basic imports, print methods and range method
 ## Configuration
 Properties can be defined in resources/application.properties
 ### jshellapi.regularSessionTimeoutSeconds

JShellAPI/src/main/java/org/togetherjava/jshellapi/rest/JShellController.java

@@ -9,35 +9,38 @@
 import org.togetherjava.jshellapi.exceptions.DockerException;
 import org.togetherjava.jshellapi.service.JShellService;
 import org.togetherjava.jshellapi.service.JShellSessionService;
+import org.togetherjava.jshellapi.service.StartupScriptId;
+import org.togetherjava.jshellapi.service.StartupScriptsService;
 
 import java.util.List;
 
 @RequestMapping("jshell")
 @RestController
 public class JShellController {
     private JShellSessionService service;
+    private StartupScriptsService startupScriptsService;
 
     @PostMapping("/eval/{id}")
-    public JShellResult eval(@PathVariable String id, @RequestBody String code) throws DockerException {
+    public JShellResult eval(@PathVariable String id, @RequestParam(required = false) StartupScriptId startupScriptId, @RequestBody String code) throws DockerException {
         validateId(id);
-        return service.session(id).eval(code).orElseThrow(() -> new ResponseStatusException(HttpStatus.CONFLICT, "An operation is already running"));
+        return service.session(id, startupScriptId).eval(code).orElseThrow(() -> new ResponseStatusException(HttpStatus.CONFLICT, "An operation is already running"));
     }
     @PostMapping("/eval")
-    public JShellResultWithId eval(@RequestBody String code) throws DockerException {
-        JShellService jShellService = service.session();
+    public JShellResultWithId eval(@RequestParam(required = false) StartupScriptId startupScriptId, @RequestBody String code) throws DockerException {
+        JShellService jShellService = service.session(startupScriptId);
         return new JShellResultWithId(jShellService.id(), jShellService.eval(code).orElseThrow(() -> new ResponseStatusException(HttpStatus.CONFLICT, "An operation is already running")));
     }
     @PostMapping("/single-eval")
-    public JShellResult singleEval(@RequestBody String code) throws DockerException {
-        JShellService jShellService = service.oneTimeSession();
+    public JShellResult singleEval(@RequestParam(required = false) StartupScriptId startupScriptId, @RequestBody String code) throws DockerException {
+        JShellService jShellService = service.oneTimeSession(startupScriptId);
         return jShellService.eval(code).orElseThrow(() -> new ResponseStatusException(HttpStatus.CONFLICT, "An operation is already running"));
     }
 
     @GetMapping("/snippets/{id}")
-    public List<String> snippets(@PathVariable String id) throws DockerException {
+    public List<String> snippets(@PathVariable String id, @RequestParam(required = false) boolean includeStartupScript) throws DockerException {
         validateId(id);
         if(!service.hasSession(id)) throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Id " + id + " not found");
-        return service.session(id).snippets().orElseThrow(() -> new ResponseStatusException(HttpStatus.CONFLICT, "An operation is already running"));
+        return service.session(id, null).snippets().map(l -> includeStartupScript || l.size() < 2 ? l : l.subList(2, l.size())).orElseThrow(() -> new ResponseStatusException(HttpStatus.CONFLICT, "An operation is already running"));
     }
 
     @DeleteMapping("/{id}")
@@ -47,11 +50,23 @@ public void delete(@PathVariable String id) throws DockerException {
         service.deleteSession(id);
     }
 
+    @GetMapping("/startup_script/{id}")
+    public String startupScript(@PathVariable StartupScriptId id) {
+        String imports = startupScriptsService.getImports(id);
+        String sep = imports.endsWith("\n") ? "\n" : "\n\n";
+        return imports + sep + startupScriptsService.getScript(id);
+    }
+
     @Autowired
     public void setService(JShellSessionService service) {
         this.service = service;
     }
 
+    @Autowired
+    public void setStartupScriptsService(StartupScriptsService startupScriptsService) {
+        this.startupScriptsService = startupScriptsService;
+    }
+
     private static void validateId(String id) throws ResponseStatusException {
         if(!id.matches("[a-zA-Z0-9][a-zA-Z0-9_.-]+")) {
             throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "Id " + id + " doesn't match the regex [a-zA-Z0-9][a-zA-Z0-9_.-]+");

JShellAPI/src/main/java/org/togetherjava/jshellapi/service/JShellService.java

@@ -30,7 +30,7 @@ public class JShellService implements Closeable {
     private final boolean renewable;
     private boolean doingOperation;
 
-    public JShellService(JShellSessionService sessionService, String id, long timeout, boolean renewable, long evalTimeout, int maxMemory, double cpus) throws DockerException {
+    public JShellService(JShellSessionService sessionService, String id, long timeout, boolean renewable, long evalTimeout, int maxMemory, double cpus, String startupImports, String startupScript) throws DockerException {
         this.sessionService = sessionService;
         this.id = id;
         this.timeout = timeout;
@@ -63,6 +63,10 @@ public JShellService(JShellSessionService sessionService, String id, long timeou
                     .start();
             writer = process.outputWriter();
             reader = process.inputReader();
+            writer.write(sanitize(startupImports));
+            writer.newLine();
+            writer.write(sanitize(startupScript));
+            writer.newLine();
         } catch (IOException e) {
             throw new DockerException(e);
         }
@@ -226,6 +230,10 @@ private void stopOperation() {
         doingOperation = false;
     }
 
+    private static String sanitize(String s) {
+        return s.replace("\\", "\\\\").replace("\n", "\\n");
+    }
+
     private static String desanitize(String text) {
         return text.replace("\\n", "\n").replace("\\\\", "\\");
     }

JShellAPI/src/main/java/org/togetherjava/jshellapi/service/JShellSessionService.java

@@ -2,6 +2,7 @@
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
+import org.springframework.lang.Nullable;
 import org.springframework.stereotype.Service;
 import org.springframework.web.server.ResponseStatusException;
 import org.togetherjava.jshellapi.Config;
@@ -15,6 +16,7 @@
 @Service
 public class JShellSessionService {
     private Config config;
+    private StartupScriptsService startupScriptsService;
     private ScheduledExecutorService scheduler;
     private final Map<String, JShellService> jshellSessions = new HashMap<>();
     private void initScheduler() {
@@ -45,17 +47,17 @@ public boolean hasSession(String id) {
         return jshellSessions.containsKey(id);
     }
 
-    public JShellService session(String id) throws DockerException {
+    public JShellService session(String id, @Nullable StartupScriptId startupScriptId) throws DockerException {
         if(!hasSession(id)) {
-            return createSession(id, config.regularSessionTimeoutSeconds(), true, config.evalTimeoutSeconds());
+            return createSession(id, config.regularSessionTimeoutSeconds(), true, config.evalTimeoutSeconds(), startupScriptId);
         }
         return jshellSessions.get(id);
     }
-    public JShellService session() throws DockerException {
-        return createSession(UUID.randomUUID().toString(), config.regularSessionTimeoutSeconds(), false, config.evalTimeoutSeconds());
+    public JShellService session(@Nullable StartupScriptId startupScriptId) throws DockerException {
+        return createSession(UUID.randomUUID().toString(), config.regularSessionTimeoutSeconds(), false, config.evalTimeoutSeconds(), startupScriptId);
     }
-    public JShellService oneTimeSession() throws DockerException {
-        return createSession(UUID.randomUUID().toString(), config.oneTimeSessionTimeoutSeconds(), false, config.evalTimeoutSeconds());
+    public JShellService oneTimeSession(@Nullable StartupScriptId startupScriptId) throws DockerException {
+        return createSession(UUID.randomUUID().toString(), config.oneTimeSessionTimeoutSeconds(), false, config.evalTimeoutSeconds(), startupScriptId);
     }
 
     public void deleteSession(String id) throws DockerException {
@@ -64,14 +66,23 @@ public void deleteSession(String id) throws DockerException {
         scheduler.schedule(service::close, 500, TimeUnit.MILLISECONDS);
     }
 
-    private synchronized JShellService createSession(String id, long sessionTimeout, boolean renewable, long evalTimeout) throws DockerException {
+    private synchronized JShellService createSession(String id, long sessionTimeout, boolean renewable, long evalTimeout, @Nullable StartupScriptId startupScriptId) throws DockerException {
         if(hasSession(id)) {    //Just in case race condition happens just before createSession
             return jshellSessions.get(id);
         }
         if(jshellSessions.size() >= config.maxAliveSessions()) {
             throw new ResponseStatusException(HttpStatus.TOO_MANY_REQUESTS, "Too many sessions, try again later :(.");
         }
-        JShellService service = new JShellService(this, id, sessionTimeout, renewable, evalTimeout, config.dockerMaxRamMegaBytes(), config.dockerCPUsUsage());
+        JShellService service = new JShellService(
+                this,
+                id,
+                sessionTimeout,
+                renewable,
+                evalTimeout,
+                config.dockerMaxRamMegaBytes(),
+                config.dockerCPUsUsage(),
+                startupScriptsService.getImports(startupScriptId),
+                startupScriptsService.getScript(startupScriptId));
         jshellSessions.put(id, service);
         return service;
     }
@@ -81,4 +92,9 @@ public void setConfig(Config config) {
         this.config = config;
         initScheduler();
     }
+
+    @Autowired
+    public void setStartupScriptsService(StartupScriptsService startupScriptsService) {
+        this.startupScriptsService = startupScriptsService;
+    }
 }

JShellAPI/src/main/java/org/togetherjava/jshellapi/service/StartupScriptId.java

@@ -0,0 +1,5 @@
+package org.togetherjava.jshellapi.service;
+
+public enum StartupScriptId {
+        EMPTY, CUSTOM_DEFAULT;
+}

JShellAPI/src/main/java/org/togetherjava/jshellapi/service/StartupScriptsService.java

@@ -0,0 +1,57 @@
+package org.togetherjava.jshellapi.service;
+
+import org.springframework.lang.Nullable;
+import org.springframework.stereotype.Service;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UncheckedIOException;
+import java.nio.charset.StandardCharsets;
+import java.util.EnumMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.function.Function;
+
+@Service
+public class StartupScriptsService {
+    private record StartupScript(String imports, String script) {}
+
+    private final Map<StartupScriptId, StartupScript> scripts;
+
+    private StartupScriptsService() {
+        scripts = new EnumMap<>(StartupScriptId.class);
+        for (StartupScriptId id : StartupScriptId.values()) {
+            try (
+                    InputStream importsStream = Objects.requireNonNull(StartupScriptsService.class.getResourceAsStream("/jshell_startup/imports/" + id + ".jsh"), "Couldn't load script " + id);
+                    InputStream scriptStream = Objects.requireNonNull(StartupScriptsService.class.getResourceAsStream("/jshell_startup/scripts/" + id + ".jsh"), "Couldn't load script " + id)) {
+                String imports = new String(importsStream.readAllBytes(), StandardCharsets.UTF_8);
+                String script = new String(scriptStream.readAllBytes(), StandardCharsets.UTF_8);
+                scripts.put(id, new StartupScript(imports, script));
+            } catch (IOException e) {
+                throw new UncheckedIOException(e);
+            }
+        }
+    }
+    private String get(@Nullable StartupScriptId id, Function<StartupScript, String> function) {
+        StartupScript startupScript = scripts.get(id);
+        return startupScript != null ? function.apply(startupScript) : function.apply(scripts.get(StartupScriptId.EMPTY));
+    }
+
+    /**
+     * Returns corresponding imports, or default imports if id is null
+     * @param id the id or the imports, can be null
+     * @return corresponding imports, or default imports if id is null
+     */
+    public String getImports(@Nullable StartupScriptId id) {
+        return get(id, StartupScript::imports);
+    }
+
+    /**
+     * Returns corresponding script, or default script if id is null
+     * @param id the id or the script, can be null
+     * @return corresponding script, or default script if id is null
+     */
+    public String getScript(@Nullable StartupScriptId id) {
+        return get(id, StartupScript::script);
+    }
+}

JShellAPI/src/main/resources/jshell_startup/imports/CUSTOM_DEFAULT.jsh

@@ -0,0 +1,20 @@
+import java.nio.charset.*;
+import java.nio.file.*;
+import java.text.*;
+import java.time.*;
+import java.time.chrono.*;
+import java.time.format.*;
+import java.time.temporal.*;
+import java.time.zone.*;
+import java.nio.charset.*;
+import java.util.concurrent.atomic.*;
+import java.util.concurrent.locks.*;
+import java.util.random.*;
+import java.math.*;
+import java.util.*;
+import java.util.concurrent.*;
+import java.util.function.*;
+import java.util.prefs.*;
+import java.util.regex.*;
+import java.util.stream.*;
+

JShellAPI/src/main/resources/jshell_startup/imports/EMPTY.jsh

@@ -0,0 +1,7 @@
+void print(Object o) { System.out.print(o); }
+void println(Object o) { System.out.println(o); }
+void printf(String s, Object... args) { System.out.printf(s, args); }
+
+Iterable<Integer> range(int startInclusive, int endExclusive) {
+    return IntStream.range(startInclusive, endExclusive)::iterator;
+}