Question

我试图从这样的网址获取图片：

var string = "https://maps.googleapis.com/maps/api/staticmap?key=AIzaSyAJeHxZaZuNsYimNCJ4r0yuO-OYM8cINOI&center=6.241381,-75.595083&zoom=13&size=600x300&path=color:0x0000ff|weight:5|6.241381,-75.595083&signature=u7sM3m2h-qFSJoARR7cqD0CSBvU="

let url = NSURL(string: string.stringByRemovingPercentEncoding!)

if let data = NSData(contentsOfURL: url){
      let image = UIImage(data: data)
}

但它返回 url 。看起来网址并不存在但是如果你去网址你会看到一个图像。

那么演员的问题是什么？或者我怎样才能得到这个图像。

Answer 1

这就是我使用AlamofireImage

在我的应用程序中加载图像的方法

let url = NSURL(string:"someUrl")
                self.imgView.af_setImageWithURL(url!, placeholderImage: nil, filter: nil,  imageTransition: .CrossDissolve(0.5), runImageTransitionIfCached: false, completion:  { (error) in
                // do Something when asynchronous image loading is completed
            })

修改你的网址包含|这对url无效，因此您可以使用PercentEncoding。

这是一个例子

let strurl = "https://maps.googleapis.com/maps/api/staticmap?key=AIzaSyAJeHxZaZuNsYimNCJ4r0yuO-OYM8cINOI&center=6.241381,-75.595083&zoom=13&size=600x300&path=color:0x0000ff|weight:5|6.241381,-75.595083&signature=u7sM3m2h-qFSJoARR7cqD0CSBvU=" let myURL = NSURL(string: strurl.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())!) self.imgView.af_setImageWithURL(myURL!, placeholderImage: nil, filter: nil, imageTransition: .CrossDissolve(0.5), runImageTransitionIfCached: false, completion: { (error) in // do Something when asynchronous image loading is completed })

Answer 2

您必须在查询中添加百分比编码，如下所示：

Swift 2.3

let domainAPI = "https://maps.googleapis.com/maps/api/staticmap?"
let query = "key=AIzaSyAJeHxZaZuNsYimNCJ4r0yuO-OYM8cINOI&center=6.241381,-75.595083&zoom=13&size=600x300&path=color:0x0000ff|weight:5|6.241381,-75.595083&signature=u7sM3m2h-qFSJoARR7cqD0CSBvU="
if let queryPercentEncoded = query.stringByAddingPercentEncodingWithAllowedCharacters(.URLQueryAllowedCharacterSet()),
    let url = NSURL(string: domainAPI + queryPercentEncoded) {
    print(url)
}

Swift 3

if let queryPercentEncoded = query.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed),
    let url = URL(string: domainAPI + queryPercentEncoded) {
    print(url)
}

Answer 3

问题是您网址的查询部分中的竖线（|）。它们应该以{{1}}转义。

这是我如何构建自动转义查询部分的URL：

%7C

如果您使用的是Swift 3，var components = NSURLComponents(string: "https://maps.googleapis.com/maps/api/staticmap")! components.query = "key=AIzaSyAJeHxZaZuNsYimNCJ4r0yuO-OYM8cINOI&center=6.241381,-75.595083&zoom=13&size=600x300&path=color:0x0000ff|weight:5|6.241381,-75.595083&signature=u7sM3m2h-qFSJoARR7cqD0CSBvU=" if let url = components.url { // ... }将重命名为NSURLComponents

Answer 4

（我没有使用基于密钥的身份验证，因此可能需要修改某些部分。）

首先，您需要一个没有签名的正确的百分比转义URL字符串：

let key = "AI...OI" // better hide your actual key in a public space...
let rawURLString = "https://maps.googleapis.com/maps/api/staticmap?key=\(key)&center=6.241381%2B-75.595083&zoom=13&size=600x300&path=color%3A0x0000ff%7Cweight%3A5%7C6.241381%2B-75.595083"
//`rawURLString` needs to be a valid string representation of URL.
assert(NSURL(string: rawURLString) != nil)

然后，为URL字符串生成base64编码的签名：

let encodedSignature: String = generateEncodedSignature(rawURLString, secret: yourSecretKey)

之后，您可以创建签名的URL字符串：

let signedURLString = "\(rawURLString)&signature=\(encodedSignature)"

（我相信你有一些功能可以在你的应用中生成签名或签名的网址，根据它修改上面的代码。）

signedURLString的内容应如下所示：

https://maps.googleapis.com/maps/api/staticmap?key=AI...OI&center=6.241381%2B-75.595083&zoom=13&size=600x300&path=color%3A0x0000ff%7Cweight%3A5%7C6.241381%2B-75.595083&&signature=u7...=

（signature可能不以“u7”开头。）

使用NSURL创建signedURLString。不要删除百分比编码。

let url = NSURL(string: signedURLString)

将字符串转换为NSURL将返回nil

4 个答案: