serializer重写FileField

我们图片用的服务器和代码服务器不是同一个,返回给前端的url就需要替换host

1.查看源码里面FileField怎么给服务器返url的,在里面替换host就行

    def to_representation(self, value):
        if not value:
            return None

        use_url = getattr(self, 'use_url', api_settings.UPLOADED_FILES_USE_URL)

        if use_url:
            if not getattr(value, 'url', None):
                # If the file has not been saved it may not have a URL.
                return None
            url = value.url
            request = self.context.get('request', None)
            if request is not None:
                return request.build_absolute_uri(url)
            return url
        return value.name

2.重写to_representation,替换原先的host

from rest_framework import serializers
class FileField(serializers.FileField):
        def to_representation(self, value: Any) -> Any:
        if not value:
            return None

        use_url = getattr(self, 'use_url', api_settings.UPLOADED_FILES_USE_URL)
        host = getattr(self, 'host', settings.NEW_FILES_HOST)

        if use_url:
            if not getattr(value, 'url', None):
                # If the file has not been saved it may not have a URL.
                return None
            url = value.url
            request = self.context.get('request', None)
            if request is not None:
                # 拿到当前的本机ip
                original_host = request.get_host()
                url = request.build_absolute_uri(url)
                if host:
                    # 替换成新的域名
                    url = url.replace(original_host, host)
            return url
        return value.name