在Vue组件中自动重新加载图像

Question

我有一个简单的商品操作组件。在此组件中，我可以创建商品并更改其图像。当我更改某种商品的图像时，后端应用程序将执行替换具有相同名称的现有图像的操作，因此图像URL不会更改。结果，在刷新页面之前，页面上的图像不会重新加载。

获得成功的服务器响应后如何重新加载强制图像？

这是很好的组件来源：

<template>
  <div class="container">
    <h3 class="mt-5">Goods</h3>

    <div class="row mt-5">
      <div class="col-md-12">
        <div class="card">
          <div class="card-header align-middle">
            <div class="card-tools">
              <button class="btn btn-success btn-sm" v-b-modal.create-good-modal>Add</button>
            </div>
          </div>
          <div class="card-body table-responsive p-0">
            <table class="table table-hover text-center">
              <thead>
                <tr>
                  <th>ID</th>
                  <th>Image</th>
                  <th>Name</th>
                </tr>
              </thead>
              <tbody>
                <tr v-for="good in goods" :key="good.id">
                  <td class="align-middle">{{ good.id }}</td>
                  <td class="align-middle">
                    <img class="img-thumbnail" width="60" :src="goodImageUrl(good.image)"
                      v-b-modal.change-good-image-modal @click="changeGoodImage(good.id)" />
                  </td>
                  <td class="align-middle">{{ good.name }}</td>
                </tr>
              </tbody>
            </table>
          </div>
        </div>
      </div>
    </div>
    <b-modal ref="createGoodModal" id="create-good-modal" title="New good" hide-footer @show="resetCreateGoodModal"
      @hide="resetCreateGoodModal">
      <b-form @submit="createGood" class="w-100">
        <b-form-group id="form-create-good-name-group" label="Name" label-for="form-create-good-name-input">
          <b-form-input id="form-create-good-name-input" type="text" v-model="createGoodForm.name" required
            placeholder="Good name">
          </b-form-input>
        </b-form-group>
        <b-form-group id="form-create-good-image-group">
          <b-form-file v-model="createGoodForm.image" required :state="Boolean(createGoodForm.image)"
            placeholder="Choose good image">
          </b-form-file>
          <div class="mt-3">Selected image: {{ createGoodForm.image ? createGoodForm.image.name : '' }}</div>
        </b-form-group>
        <b-button type="submit" variant="primary">Create</b-button>
      </b-form>
    </b-modal>
    <b-modal ref="changeGoodImageModal" id="change-good-image-modal" title="Change good image"
      @hide="resetChangeGoodImageModal" hide-footer>
      <b-form @submit="updateGoodImage" class="w-100">
        <b-form-group id="form-change-good-image-group">
          <b-form-file v-model="changeGoodImageForm.image" required :state="Boolean(changeGoodImageForm.image)"
            placeholder="Choose good image">
          </b-form-file>
          <div class="mt-3">Selected file: {{ changeGoodImageForm.image ? changeGoodImageForm.image.name : ''
                      }}
          </div>
        </b-form-group>
        <b-button type="submit" variant="primary">Save</b-button>
      </b-form>
    </b-modal>
  </div>
</template>

<script>
  import {objectToFormData} from "object-to-formdata";
    export default {
    data() {
        return {
    goods: [],
          createGoodForm: new Form({
    name: "",
            image: null
          }),
          changeGoodImageForm: new Form({
    id: {},
            image: null
          })
        };
      },
      methods: {
    getGoods() {
    axios
      .get("goods/list")
      .then(response => {
        this.goods = response.data;
      })
      .catch(error => {
        console.error(error);
      });
        },
        createGood() {
    this.createGoodForm
      .post("goods", {
        transformRequest: [
          function (data, headers) {
            return objectToFormData(data);
          }
        ]
      })
      .then(() => {
        this.$refs.createGoodModal.hide();
        this.getGoods();
      })
      .catch(error => {
        console.log(error);
      });
        },
        changeGoodImage(id) {
    this.changeGoodImageForm.id = id;
        },
        updateGoodImage() {
    this.changeGoodImageForm
      .post("goods/" + this.changeGoodImageForm.id + "/image", {
        transformRequest: [
          function (data, headers) {
            return objectToFormData(data);
          }
        ]
      })
      .then(() => {
        this.$refs.changeGoodImageModal.hide();
        this.getGoods();
      })
      .catch(error => {
        console.log(error);
      });
        },
        goodImageUrl(filename) {
          return "http://127.0.0.1:8098/api/img/goods/" + filename;
        },
        resetCreateGoodModal() {
    this.createGoodForm.reset();
        },
        resetChangeGoodImageModal() {
    this.changeGoodImageForm.reset();
        }
      },
      created() {
    this.getGoods();
      }
    };
</script>

Answer 1

我的建议只是在图像URL后面附加一个随机缓存破坏符-一些无用的查询参数，将迫使浏览器获取新图像。假设您的后端不会拒绝该请求，但是大多数情况下此方法有效。类似于/myimage.png?cacheBuster=<somethingRandom>。请注意，在下面的代码段中，实际上不会加载新的cat图像，因为该服务器每次都没有新的图像。这只是一个示范。

var app = new Vue({
  el: '#app',
  data() {
    return { imageSource: 'https://upload.wikimedia.org/wikipedia/commons/thumb/6/69/June_odd-eyed-cat_cropped.jpg/120px-June_odd-eyed-cat_cropped.jpg' }
  },
  methods: {
    bustThatCache() {
      this.imageSource = `${this.imageSource}?cacheBust=${Math.random()}`
    }
  }
})

<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="app">
  <h1> here is a cat picture</h1>
  <p>Image Src:{{imageSource}}</p>
  <img :src="imageSource"></img>
  <button @click="bustThatCache">Load new image</button>
</div>