add self-rag (#1070)

### What problem does this PR solve?

#1069 

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

rag/nlp/query.py

@@ -48,7 +48,7 @@ class EsQueryer:
     @staticmethod
     def rmWWW(txt):
         patts = [
-            (r"是*(什么样的|哪家|一下|那家|啥样|咋样了|什么时候|何时|何地|何人|是否|是不是|多少|哪里|怎么|哪儿|怎么样|如何|哪些|是啥|啥是|啊|吗|呢|吧|咋|什么|有没有|呀)是*", ""),
+            (r"是*(什么样的|哪家|一下|那家|请问|啥样|咋样了|什么时候|何时|何地|何人|是否|是不是|多少|哪里|怎么|哪儿|怎么样|如何|哪些|是啥|啥是|啊|吗|呢|吧|咋|什么|有没有|呀)是*", ""),
             (r"(^| )(what|who|how|which|where|why)('re|'s)? ", " "),
             (r"(^| )('s|'re|is|are|were|was|do|does|did|don't|doesn't|didn't|has|have|be|there|you|me|your|my|mine|just|please|may|i|should|would|wouldn't|will|won't|done|go|for|with|so|the|a|an|by|i'm|it's|he's|she's|they|they're|you're|as|by|on|in|at|up|out|down) ", " ")
         ]
@@ -68,7 +68,9 @@ class EsQueryer:
         if not self.isChinese(txt):
             tks = rag_tokenizer.tokenize(txt).split(" ")
             tks_w = self.tw.weights(tks)
-            tks_w = [(re.sub(r"[ \\\"']+", "", tk), w) for tk, w in tks_w]
+            tks_w = [(re.sub(r"[ \\\"'^]", "", tk), w) for tk, w in tks_w]
+            tks_w = [(re.sub(r"^[a-z0-9]$", "", tk), w) for tk, w in tks_w if tk]
+            tks_w = [(re.sub(r"^[\+-]", "", tk), w) for tk, w in tks_w if tk]
             q = ["{}^{:.4f}".format(tk, w) for tk, w in tks_w if tk]
             for i in range(1, len(tks_w)):
                 q.append("\"%s %s\"^%.4f" % (tks_w[i - 1][0], tks_w[i][0], max(tks_w[i - 1][1], tks_w[i][1])*2))
@@ -118,7 +120,8 @@ class EsQueryer:
                 if sm:
                     tk = f"{tk} OR \"%s\" OR (\"%s\"~2)^0.5" % (
                         " ".join(sm), " ".join(sm))
-                tms.append((tk, w))
+                if tk.strip():
+                    tms.append((tk, w))
 
             tms = " ".join([f"({t})^{w}" for t, w in tms])