fix(core): improve error handling and stability in core components

Enhance error handling and stability across multiple components:
- Add safety checks in async_configs.py for type and params existence
- Fix browser manager initialization and cleanup logic
- Add default LLM config fallback in extraction strategy
- Add comprehensive Docker deployment guide and server tests

BREAKING CHANGE: BrowserManager.start() now automatically closes existing instances

crawl4ai/async_configs.py

@@ -122,23 +122,25 @@ def from_serializable_dict(data: Any) -> Any:
     # Handle typed data
     if isinstance(data, dict) and "type" in data:
         # Handle plain dictionaries
-        if data["type"] == "dict":
+        if data["type"] == "dict" and "value" in data:
             return {k: from_serializable_dict(v) for k, v in data["value"].items()}
 
         # Import from crawl4ai for class instances
         import crawl4ai
 
-        cls = getattr(crawl4ai, data["type"])
+        if hasattr(crawl4ai, data["type"]):
+            cls = getattr(crawl4ai, data["type"])
 
-        # Handle Enum
-        if issubclass(cls, Enum):
-            return cls(data["params"])
+            # Handle Enum
+            if issubclass(cls, Enum):
+                return cls(data["params"])
 
-        # Handle class instances
-        constructor_args = {
-            k: from_serializable_dict(v) for k, v in data["params"].items()
-        }
-        return cls(**constructor_args)
+            if "params" in data:
+                # Handle class instances
+                constructor_args = {
+                    k: from_serializable_dict(v) for k, v in data["params"].items()
+                }
+                return cls(**constructor_args)
 
     # Handle lists
     if isinstance(data, list):

crawl4ai/browser_manager.py

@@ -491,10 +491,12 @@ class BrowserManager:
 
         Note: This method should be called in a separate task to avoid blocking the main event loop.
         """
-        if self.playwright is None:
-            from playwright.async_api import async_playwright
+        if self.playwright is not None:
+            await self.close()
+            
+        from playwright.async_api import async_playwright
 
-            self.playwright = await async_playwright().start()
+        self.playwright = await async_playwright().start()
 
         if self.config.cdp_url or self.config.use_managed_browser:
             self.config.use_managed_browser = True

crawl4ai/extraction_strategy.py

@@ -7,7 +7,9 @@ import time
 
 from .prompts import PROMPT_EXTRACT_BLOCKS, PROMPT_EXTRACT_BLOCKS_WITH_INSTRUCTION, PROMPT_EXTRACT_SCHEMA_WITH_INSTRUCTION, JSON_SCHEMA_BUILDER_XPATH, PROMPT_EXTRACT_INFERRED_SCHEMA
 from .config import (
-    DEFAULT_PROVIDER, CHUNK_TOKEN_THRESHOLD,
+    DEFAULT_PROVIDER,
+    DEFAULT_PROVIDER_API_KEY,
+    CHUNK_TOKEN_THRESHOLD,
     OVERLAP_RATE,
     WORD_TOKEN_RATE,
 )
@@ -542,6 +544,11 @@ class LLMExtractionStrategy(ExtractionStrategy):
         """
         super().__init__( input_format=input_format, **kwargs)
         self.llm_config = llm_config
+        if not self.llm_config:
+            self.llm_config = create_llm_config(
+                provider=DEFAULT_PROVIDER,
+                api_token=os.environ.get(DEFAULT_PROVIDER_API_KEY),
+            )
         self.instruction = instruction
         self.extract_type = extraction_type
         self.schema = schema