Question

我正在建立一个网站，用户可以上传关于阅读小说的见解和评论，并且用户可以自由获取小说的图像。

如果选择了图像，则发布架构具有image和imageId属性，用于Cloudinary上传以及将来的操作，例如从Cloudinary库中更改（更新路由）或删除（销毁路由）。如果未选择任何图像，则会发生默认图像。

问题是，我设法使default image函数起作用，但是我不希望将多个相同的默认图像上载到Cloudinary库，因此我将default_image.jpg放置在本地服务器文件夹(/public/images)中确切地说），并且该default_image.jpg不应放在Cloudinary库中，这样可以节省很多容量。

但是，对于这些没有选定图片的帖子，我不知道应该为其imageId属性分配什么。

我尝试了undefined和null，当然它们没有用，因为这样，如果它们全部都找不到某些novel.imageId未定义或为空。

// Schema for data
var fictionSchema = new mongoose.Schema({
    ...
    ...
    image: String,
    // for cloudinary API to track which image to delete or update
    imageId: String,
    ...
    ...
});

// CREATE route
router.post("/", middleware.isLoggedIn, upload.single('image'), (req, res) => {
    if (req.file){
        // req.file.path comes from multer npm
        cloudinary.v2.uploader.upload(req.file.path, function (err, result) {
            if (err) {
                ...
            }
            // add cloudinary url for the image to the novel object under image property
            req.body.novel.image = result.secure_url;
            req.body.novel.imageId = result.public_id;
        });
    } else {
        // setup default image for new novels
        req.body.novel.image = "/images/noimage.jpg";

        // imageId here should be ... empty? Undefined? Null? A fixed ID but may be delete when accessing Destroy route?
        req.body.novel.imageId = undefined;
    }
    ...
    ...
    Novel.create(req.body.novel, function (err, newlyAddedNovel) {
        if (err) {
            req.flash('error', err.message);
            ...
        } else {
            req.flash("success", "Novel added successfully.");
            ...
        }
    });
});

// DESTROY route
router.delete("/:id", middleware.checkNovelOwnership, (req, res) => {
    // find and delete the correct novel along with the image on cloudinary
    Novel.findById(req.params.id, async (err, novel) => {
        if (err) {
            req.flash("error", err.message);
            return res.redirect("back");
        }
        try {
            await cloudinary.v2.uploader.destroy(novel.imageId);
            // delete the novel found
            novel.remove();
            // delete the image from cloudinary
            req.flash("success", "Novel deleted successfully.");
            ...
            ...
        } catch (err) {
            ..
        }
    });
});

Answer 1

好消息，我解决了这个问题！她的光芒！虽然花了我大约2个小时...

所以，最终一切都按我的意愿进行了，如此精致。

代码如下：

•创建路线

对于新帖子，我首先用默认图像设置每本新小说，然后如果提供了图像（要求文件），请对其进行更改并上传。

之后，请记住在mongo数据库中创建该新颖数据。（在我的情况下为Novel.create（）。）

router.post("/", middleware.isLoggedIn, upload.single('image'), async function (req, res) {
    // set every new novel with default image first
    req.body.novel.image = "https://res.cloudinary.com/dvfkbz6la/image/upload/v1565434656/noimage_ew1uri.jpg";
    req.body.novel.imageId = "noimage_ew1uri";
    req.body.novel.user = {
        id: req.user._id,
        username: req.user.username
    };

    if (req.file) {
        // req.file.path comes from multer npm
        await cloudinary.v2.uploader.upload(req.file.path, function (err, result) {
            if (err) {
                req.flash('error', err.message);
                return res.redirect('back');
            }
            // add cloudinary url for the image to the novel object under image property
            // add image's public_id (imageId in novel model) to novel object
            req.body.novel.image = result.secure_url;
            req.body.novel.imageId = result.public_id;
        });
    }
    Novel.create(req.body.novel, function (err, newlyAddedNovel) {
        if (err) {
            ...
        } else {
            ...
        }
    });
});

•更新路线

在try块中，如果添加了（novel.imageId =“ DEFAULT_IMAGEID”）{}否则{}。

// UPDATE route
router.put("/:id", middleware.checkNovelOwnership, upload.single('image'), (req, res) => {
    // find the correct novel
    Novel.findById(req.params.id, async (err, novel) => {
        if (err) {
            ...
        } else {
            // if there's a req.file, we know user is trying to upload a new image
            if (req.file) {
                try {
                    // if imageId is default, await the result to be uploaded
                    if (novel.imageId = "noimage_ew1uri") {
                        var result = await cloudinary.v2.uploader.upload(req.file.path);
                    } else {
                        //  if not default, find the old image using imageId and delete
                        await cloudinary.v2.uploader.destroy(novel.imageId);
                        var result = await cloudinary.v2.uploader.upload(req.file.path);
                    }
                    novel.imageId = result.public_id;
                    novel.image = result.secure_url;
                } catch (err) {
                    ...
                }
            }
            novel.title = req.body.title;
            novel.author = req.body.author;
            novel.price = req.body.price;
            novel.description = req.body.description;

            // remember to save the changed novel
            novel.save();
            req.flash("success", "Successfully Updated!");
            res.redirect("/novels/" + novel._id);
        }
    });
});

•毁灭路线

在try块中，如果添加了（novel.imageId！=“ DEFAULT_IMAGEID”）{}否则{}。

// DESTROY route
router.delete("/:id", middleware.checkNovelOwnership, (req, res) => {
    // find and delete the correct novel along with the image on cloudinary
    Novel.findById(req.params.id, async (err, novel) => {
        if (err) {
            req.flash("error", err.message);
            return res.redirect("back");
        }
        try {
            // if novel.imageId isn't default, destroy it from Cloudinary
            if (novel.imageId != "noimage_ew1uri") {
                await cloudinary.v2.uploader.destroy(novel.imageId);
            }
            // delete the novel found
            novel.remove();
            ...
        } catch (err) {
            ...
        }
    });
});

剩下的唯一问题是，我不知道为什么，但是当点击UPDATE路由时，并且当imageId不是默认值并且用户更改了图像时，

旧映像不会被破坏并保留在Cloudinary库中。真奇怪。

我确定已设置此代码

Novel.findById(req.params.id, async (err, novel) => {
        if (err) {
            ...
        } else {
            if (req.file) {
                try {
                    // if imageId is default, await the result to be uploaded
                    if (novel.imageId = "noimage_ew1uri") {
                        ...
                    } else {
                        //  if not default, find the old image using imageId and delete
                        await cloudinary.v2.uploader.destroy(novel.imageId);
                        var result = await cloudinary.v2.uploader.upload(req.file.path);
                    }
...
...

Dunno为什么要等待cloudinary.v2.uploader.destroy（novel.imageId）;不能按预期工作。嗯...

Answer 2

您网站中已经可用的图像被缓存在一个或多个CDN边缘中。因此，即使您从Cloudinary帐户中删除了映像，缓存的副本仍可能可用。默认情况下，所有交付的图像都会缓存30天。

在将invalidate参数设置为true的销毁API时，该图像将被删除并从CDN中清除，从而允许显示新图像。

或者，在更新时，通过在上载新文件时将overwrite和invalidate参数设置为true，可以实现相同的结果（无需调用destroy方法）

缺少必需的参数-public_id，以及为Cloudinary分配给imageId的内容

2 个答案: