API: Add banned_tokens

Appends the banned tokens to the generation. This is equivalent of
setting logit bias to -100 on a specific set of tokens.

Signed-off-by: kingbri <bdashore3@proton.me>

common/sampling.py

@@ -177,6 +177,13 @@ class BaseSamplerRequest(BaseModel):
         examples=[1.0],
     )
 
+    banned_tokens: Optional[Union[List[int], str]] = Field(
+        default_factory=lambda: get_default_sampler_value("banned_tokens", []),
+        validation_alias=AliasChoices("banned_tokens", "custom_token_bans"),
+        description="Aliases: custom_token_bans",
+        examples=[[128, 330]],
+    )
+
     # TODO: Return back to adaptable class-based validation But that's just too much
     # abstraction compared to simple if statements at the moment
     def validate_params(self):
@@ -245,6 +252,9 @@ class BaseSamplerRequest(BaseModel):
         if isinstance(self.stop, str):
             self.stop = [self.stop]
 
+        if isinstance(self.banned_tokens, str):
+            self.banned_tokens = list(map(int, self.banned_tokens.split(",")))
+
         gen_params = {
             "max_tokens": self.max_tokens,
             "generate_window": self.generate_window,
@@ -254,6 +264,7 @@ class BaseSamplerRequest(BaseModel):
             "skip_special_tokens": self.skip_special_tokens,
             "token_healing": self.token_healing,
             "logit_bias": self.logit_bias,
+            "banned_tokens": self.banned_tokens,
             "temperature": self.temperature,
             "temperature_last": self.temperature_last,
             "min_temp": self.min_temp,