Rails Carrierwave 上传多个文件 undefined method `[]' for nil:NilClass

Question

请有人解释一下为什么会这样

nil:NilClass 的未定义方法 `[]'

在使用 rails、carrierwave 和 react 上传文件时发生了什么？

其余代码非常标准，因此在上传图片的日志中，post_attachments 中的图片属性始终显示为空白。

我怀疑问题出在 post create 上的 post_attachments 上的 rails 循环，你们怎么看？

我变成了

 params[:post_attachments].each do |image|
    img = PostAttachment.new
    img.image = image
    @post.post_attachments << img
  end 

仍然显示错误。

所以请，有人知道为什么这与载波和反应？

这里是后期控制器

  def create


    @post = current_user.posts.build(post_params)


    if @post.save
      #unless params[:post_attachments].nil?
        params[:post_attachments]['image'].each do |a|
          @post_attachment = @post.post_attachments.create!(:image => a, :post_id => @post.id)

      #end


    end

    render json: "Posted successfully", status: 201
    else
      render json: @post.errors, status: :unprocessable_entity
    end
  end

和反应

  async sendImage(forma) {
    let self = this;
    let errs = 0;
    let auth_token = await AsyncStorage.getItem(AUTH_TOKEN);

    try {
      let response = await fetch("https://localhost:3000/posts", {
        method: "POST",
        headers: {
          Accept: "application/json",

          //"Content-Type": "multipart/form-data",
          Access: auth_token
        },
        body: forma
      });
      let res = await response.text();
      if (response.status >= 200 && response.status < 300) {
      } else {
        //Handle errors
        let error = res;
        throw error;
      }
    } catch (errors) {
      //errors are in JSON form so we must parse them first.
      let formErrors = JSON.parse(errors);
      //We will store all the errors in the array.
      let errorsArray = [];
      for (var key in formErrors) {
        //If array is bigger than one we need to split it.
        if (formErrors[key].length > 1) {
          formErrors[key].map(error => errorsArray.push(`${key} ${error}`));
        } else {
          errorsArray.push(`${key} ${formErrors[key]}`);
        }
      }
      this.setState({ errors: errorsArray });
      //this.setState({showProgress: false});
    }
  }

  async uploadImage() {
    const { params } = this.props.navigation.state;
    let image = params ? params.image : null;
    let photos = params ? params.photos : [];

    var self = this;
    let forma = new FormData();

    forma.append("post[title]", String(this.state.title));
    forma.append("post[body]", String(this.state.body));

    forma.append("post[post_attachments][image][]", 'teste');

    for (let i = 0; i < photos.length; ++i) {
      await fs
        .readFile(photos[i], "base64")
        .then(async blob => {
          //forma.append("post[post_attachments][image][]", 'teste');

        .catch(error => {
          console.log("loop err", error);
        });
    }

    self.sendImage(forma);
  }

日志截图

Answer 1

参数是这样的： -

paramaters: {"post" = > .... "post_attachments" => {"image" => ["test"]}}

所以image_params应该是这样的-

image_params = params[:post][:post_attachments][:image]

和

  unless image_params.blank?
    image_params.each do |image|
      img = PostAttachment.new
      img.image = image
      @post.post_attachments << img
    end 
  end