如何从 iOS 中的 url 请求中提取数据

Question

我正在编写一个扫描条形码的应用程序，然后查询 Outpan.com 以便从条形码编号中获取信息。如何从 url 请求中提取信息？以下是成功扫描后的输出示例。例如，我如何将名称存储到 NSString 中？

这是我用来访问信息的代码。

- (void) sendRequest {


NSString *myString = @"https://api.outpan.com/v2/products/";

NSString *secondhalf= _barcode;


NSString *thirdHalf = @"?apikey=935b8b8e102f93220b751a4e1c66126a";

NSString *test = [myString stringByAppendingString:secondhalf];
NSString *text = [test stringByAppendingString:thirdHalf];

if (![text isEqualToString:@""]) {

    NSURL *url = [NSURL URLWithString:text];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [self.webView loadRequest:request];

}

}

通常我会尝试使用类似

的东西

   NSString* value = [webView stringByEvaluatingJavaScriptFromString:@"document.getElementById('myId').value"];

如果 html 看起来像这样

<html>
  <body>
      <input id="myId" type="text" value="TextValue"/>
  </body>
</html>

但是html是这样的

<html><head></head><body><pre style="word-wrap: break-word; white-space: pre-    wrap;">{
    "gtin": "0014633156720",
    "outpan_url": "https:\/\/www.outpan.com\/view_product.php?    barcode=0014633156720",
    "name": "Battlefield: Bad Company 2",
    "attributes": {
        "Distribution Media\/Method": "Blu-ray Disc",
        "ESRB Rating": "RP (Rating Pending)",
        "Manufacturer": "Electronic Arts",
        "Manufacturer Part Number": "15672",
        "Platform": "PlayStation 3",
        "Platform Supported": "PlayStation 3",
        "Software Main Type": "Game",
        "Software Sub Type": "First Person Shooter"
    },
    "images": [],
    "videos": [],
    "categories": []
}</pre></body></html>

Answer 1

问题是您正在尝试使用 UIWebView 发出 api 请求。 api 可能会将您的 Accepts header 视为 text/html，因此会在网页中向您发送 api 响应，而不仅仅是原始的 JSON。尝试使用 NSURLSession 发出请求。

- (void)sendRequest:(id)sender {

    NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration];

    NSURLSession *session = [NSURLSession sessionWithConfiguration:sessionConfig delegate:nil delegateQueue:nil];

    NSString *urlString = [NSString stringWithFormat: @"https://api.outpan.com/v2/products/%@", _barcode];

    NSURL *url = [NSURL URLWithString: urlString];

    NSURLComponents *components = [[NSURLComponents alloc] initWithURL: url resolvingAgainstBaseURL: NO];

    NSURLQueryItem *query = [[NSURLQueryItem alloc] initWithName: @"apikey" value: @"935b8b8e102f93220b751a4e1c66126a"];

    components.queryItems = @[query];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL: components.URL];

    request.HTTPMethod = @"GET";

    NSURLSessionDataTask* task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

        if (error == nil) {

            NSDictionary *responseBody = [NSJSONSerialization JSONObjectWithData: data options: 0 error: nil];

            NSLog(@"got response: %@", responseBody);

        } else {
            // Failure
            NSLog(@"URL Session Task Failed: %@", [error localizedDescription]);
        }
    }];

    [task resume];
}

未测试，因为我没有真正的条形码，但您应该在 responseBody 字典中看到您请求的 JSON。

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