My Opinion on iCloud

Recently, I was working on a project related to iCloud, mainly to create a client to access files on iCloud, such as music, photos, and documents.

The project leader is a technical engineer who designs products while coding.ProgramClerk, I just did what I needed, but in private, I spoke deeply about this product.

Product designers do not understand the core of iCloud at all, and there is still a shortage of technical personnel.

Next, let's talk about my understanding of iCloud. You are also welcome to discuss it and criticize and correct it.

Alibaba Cloud is a cloud service launched by Apple. Its core is to store user data (photos, music, documents, programs, and settings) on all users' devices (iPhone, itouch, Mac, and PC.

Each user can use 5 GB of storage space for free. this space allows you to back up programs, emails, and calendars. in this way, after setting up an iCloud account on a new machine, I can synchronize the previously backed up data. in addition, when you download a program, iCloud will automatically synchronize it to your other Apple devices. this feature is very flattering. having said so much, iCloud seems to be something like a network disk, but there is only one more backup and push update. actually not. although the 5g space is provided to users for free, users cannot "directly" Use it. what I call "direct" means that, like Dropbox, a client allows users to store any file. but iCloud doesn't work. You can store files, but you must use a program. correspondingly, apps with the iCloud function can only access files uploaded by their own programs, which is called shoebox. this follows Apple's consistent style, because IOS itself is a closed system, and the program can only run in the sandbox, it is not surprising that iCloud is tossing a shoebox, the logic is obvious.

Therefore, the core of iCloud is to keep devices synchronized, rather than store them. with iCloud, the first thing I can think of is to use it to save the game records so that the game remains the same on different devices. for example, if I have a FireWire attack on the iPad, I have to try again on ipad2. if you have iCloud, you only need to synchronize my game records, no matter which machine I can continue to play.

For other books, news, and other apps, iCloud does not seem to be a blessing. before talking about this issue, we need to discuss how to read files on iCloud. according to the development documentation, each machine has a file image to help with updates. when you open an iCloud file, a file image is first downloaded to the image as a "local" file, read and write are both local, and uploaded to icoud for synchronous update only when saved. then I have several files. After reading them in sequence, the local image should exist. if I continue to read images, will there be more and more files in the image to occupy a large local storage space? Of course not. Apple has its storage policy. Its iCloud guidline mentioned:

<Program>/Documents files are automatically backed up, so only necessary files can be saved. those that can be generated or downloaded repeatedly should be put in the library or cache. in addition, when the storage space is insufficient, IOS will automatically delete files in the cache and library to save space. therefore, we can assume that the files downloaded from the cloud to the image will not be saved and may be deleted. this is a deep understanding during development: Using nsfilemanager, you can detect the existence of an iCloud file, but cannot read its data. the reason is that the local image has not been downloaded. therefore, we do not need to store a lot of data without limit and synchronize it to iCloud. Only necessary files can be stored. for example, in the pursuit of special effects, the data of a newspaper in the first issue of a magazine is huge, which is not in line with the design idea of the iCloud product. for example, if photo stream is enabled, photo on iPhone and itouch will only store the latest 1000 photos, and all photos can be stored on Mac or PC. this is also based on the storage space. therefore, for news apps, if there are dozens of MB of data in the first phase and users subscribe to more than a dozen stages, full synchronization to the cloud is not a small pressure, so we need to carefully store data.

 

Finally, back to the project mentioned at the beginning, I feel like I am looking for guilt, and I just want to do so. the starting point of the designer is to think that the 5g space users can control themselves and thus develop a so-called client in a whimsical manner (in fact, think carefully, if this client is really necessary, why don't apple do it ?), I did not have a deep understanding of the meaning of iCloud and the changes he would bring to the program.