root / trunk / Pithos.Network / RestClient.cs @ aba9e6d9
History | View | Annotate | Download (16 kB)
1 |
// ----------------------------------------------------------------------- |
---|---|
2 |
// <copyright file="RestClient.cs" company="Microsoft"> |
3 |
// TODO: Update copyright text. |
4 |
// </copyright> |
5 |
// ----------------------------------------------------------------------- |
6 |
|
7 |
using System.Collections.Specialized; |
8 |
using System.Diagnostics; |
9 |
using System.Diagnostics.Contracts; |
10 |
using System.IO; |
11 |
using System.Net; |
12 |
using System.Runtime.Serialization; |
13 |
using System.Threading.Tasks; |
14 |
using log4net; |
15 |
|
16 |
|
17 |
namespace Pithos.Network |
18 |
{ |
19 |
using System; |
20 |
using System.Collections.Generic; |
21 |
using System.Linq; |
22 |
using System.Text; |
23 |
|
24 |
/// <summary> |
25 |
/// TODO: Update summary. |
26 |
/// </summary> |
27 |
public class RestClient:WebClient |
28 |
{ |
29 |
public int Timeout { get; set; } |
30 |
|
31 |
public bool TimedOut { get; set; } |
32 |
|
33 |
public HttpStatusCode StatusCode { get; private set; } |
34 |
|
35 |
public string StatusDescription { get; set; } |
36 |
|
37 |
public long? RangeFrom { get; set; } |
38 |
public long? RangeTo { get; set; } |
39 |
|
40 |
public int Retries { get; set; } |
41 |
|
42 |
private readonly Dictionary<string, string> _parameters=new Dictionary<string, string>(); |
43 |
public Dictionary<string, string> Parameters |
44 |
{ |
45 |
get |
46 |
{ |
47 |
Contract.Ensures(_parameters!=null); |
48 |
return _parameters; |
49 |
} |
50 |
} |
51 |
|
52 |
private static readonly ILog Log = LogManager.GetLogger("RestClient"); |
53 |
|
54 |
|
55 |
[ContractInvariantMethod] |
56 |
private void Invariants() |
57 |
{ |
58 |
Contract.Invariant(Headers!=null); |
59 |
} |
60 |
|
61 |
public RestClient():base() |
62 |
{ |
63 |
|
64 |
} |
65 |
|
66 |
|
67 |
public RestClient(RestClient other) |
68 |
: base() |
69 |
{ |
70 |
if (other==null) |
71 |
throw new ArgumentNullException("other"); |
72 |
Contract.EndContractBlock(); |
73 |
|
74 |
CopyHeaders(other); |
75 |
Timeout = other.Timeout; |
76 |
Retries = other.Retries; |
77 |
BaseAddress = other.BaseAddress; |
78 |
|
79 |
foreach (var parameter in other.Parameters) |
80 |
{ |
81 |
Parameters.Add(parameter.Key,parameter.Value); |
82 |
} |
83 |
|
84 |
this.Proxy = other.Proxy; |
85 |
} |
86 |
|
87 |
protected override WebRequest GetWebRequest(Uri address) |
88 |
{ |
89 |
TimedOut = false; |
90 |
var webRequest = base.GetWebRequest(address); |
91 |
var request = (HttpWebRequest)webRequest; |
92 |
if (IfModifiedSince.HasValue) |
93 |
request.IfModifiedSince = IfModifiedSince.Value; |
94 |
request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip; |
95 |
if(Timeout>0) |
96 |
request.Timeout = Timeout; |
97 |
|
98 |
if (RangeFrom.HasValue) |
99 |
{ |
100 |
if (RangeTo.HasValue) |
101 |
request.AddRange(RangeFrom.Value, RangeTo.Value); |
102 |
else |
103 |
request.AddRange(RangeFrom.Value); |
104 |
} |
105 |
return request; |
106 |
} |
107 |
|
108 |
public DateTime? IfModifiedSince { get; set; } |
109 |
|
110 |
protected override WebResponse GetWebResponse(WebRequest request, IAsyncResult result) |
111 |
{ |
112 |
return ProcessResponse(()=>base.GetWebResponse(request, result)); |
113 |
} |
114 |
|
115 |
protected override WebResponse GetWebResponse(WebRequest request) |
116 |
{ |
117 |
return ProcessResponse(() => base.GetWebResponse(request)); |
118 |
} |
119 |
|
120 |
private WebResponse ProcessResponse(Func<WebResponse> getResponse) |
121 |
{ |
122 |
try |
123 |
{ |
124 |
var response = (HttpWebResponse)getResponse(); |
125 |
StatusCode = response.StatusCode; |
126 |
LastModified = response.LastModified; |
127 |
StatusDescription = response.StatusDescription; |
128 |
return response; |
129 |
} |
130 |
catch (WebException exc) |
131 |
{ |
132 |
if (exc.Response != null) |
133 |
{ |
134 |
var response = (exc.Response as HttpWebResponse); |
135 |
if (AllowedStatusCodes.Contains(response.StatusCode)) |
136 |
{ |
137 |
StatusCode = response.StatusCode; |
138 |
LastModified = response.LastModified; |
139 |
StatusDescription = response.StatusDescription; |
140 |
|
141 |
return response; |
142 |
} |
143 |
if (exc.Response.ContentLength > 0) |
144 |
{ |
145 |
string content = GetContent(exc.Response); |
146 |
Log.ErrorFormat(content); |
147 |
} |
148 |
} |
149 |
throw; |
150 |
} |
151 |
} |
152 |
|
153 |
private readonly List<HttpStatusCode> _allowedStatusCodes=new List<HttpStatusCode>{HttpStatusCode.NotModified}; |
154 |
public List<HttpStatusCode> AllowedStatusCodes |
155 |
{ |
156 |
get |
157 |
{ |
158 |
return _allowedStatusCodes; |
159 |
} |
160 |
} |
161 |
|
162 |
public DateTime LastModified { get; private set; } |
163 |
|
164 |
private static string GetContent(WebResponse webResponse) |
165 |
{ |
166 |
if (webResponse == null) |
167 |
throw new ArgumentNullException("webResponse"); |
168 |
Contract.EndContractBlock(); |
169 |
|
170 |
string content; |
171 |
using (var stream = webResponse.GetResponseStream()) |
172 |
using (var reader = new StreamReader(stream)) |
173 |
{ |
174 |
content = reader.ReadToEnd(); |
175 |
} |
176 |
return content; |
177 |
} |
178 |
|
179 |
public string DownloadStringWithRetry(string address,int retries=0) |
180 |
{ |
181 |
|
182 |
if (address == null) |
183 |
throw new ArgumentNullException("address"); |
184 |
|
185 |
var actualAddress = GetActualAddress(address); |
186 |
|
187 |
TraceStart("GET",actualAddress); |
188 |
|
189 |
var actualRetries = (retries == 0) ? Retries : retries; |
190 |
|
191 |
|
192 |
var task = Retry(() => |
193 |
{ |
194 |
var uriString = String.Join("/", BaseAddress.TrimEnd('/'), actualAddress); |
195 |
var content = base.DownloadString(uriString); |
196 |
|
197 |
if (StatusCode == HttpStatusCode.NoContent) |
198 |
return String.Empty; |
199 |
return content; |
200 |
|
201 |
}, actualRetries); |
202 |
|
203 |
var result = task.Result; |
204 |
return result; |
205 |
} |
206 |
|
207 |
public void Head(string address,int retries=0) |
208 |
{ |
209 |
AllowedStatusCodes.Add(HttpStatusCode.NotFound); |
210 |
RetryWithoutContent(address, retries, "HEAD"); |
211 |
} |
212 |
|
213 |
public void PutWithRetry(string address, int retries = 0) |
214 |
{ |
215 |
RetryWithoutContent(address, retries, "PUT"); |
216 |
} |
217 |
|
218 |
public void DeleteWithRetry(string address,int retries=0) |
219 |
{ |
220 |
RetryWithoutContent(address, retries, "DELETE"); |
221 |
} |
222 |
|
223 |
public string GetHeaderValue(string headerName,bool optional=false) |
224 |
{ |
225 |
if (this.ResponseHeaders==null) |
226 |
throw new InvalidOperationException("ResponseHeaders are null"); |
227 |
Contract.EndContractBlock(); |
228 |
|
229 |
var values=this.ResponseHeaders.GetValues(headerName); |
230 |
if (values != null) |
231 |
return values[0]; |
232 |
|
233 |
if (optional) |
234 |
return null; |
235 |
//A required header was not found |
236 |
throw new WebException(String.Format("The {0} header is missing", headerName)); |
237 |
} |
238 |
|
239 |
public void SetNonEmptyHeaderValue(string headerName, string value) |
240 |
{ |
241 |
if (String.IsNullOrWhiteSpace(value)) |
242 |
return; |
243 |
Headers.Add(headerName,value); |
244 |
} |
245 |
|
246 |
private void RetryWithoutContent(string address, int retries, string method) |
247 |
{ |
248 |
if (address == null) |
249 |
throw new ArgumentNullException("address"); |
250 |
|
251 |
var actualAddress = GetActualAddress(address); |
252 |
var actualRetries = (retries == 0) ? Retries : retries; |
253 |
|
254 |
var task = Retry(() => |
255 |
{ |
256 |
var uriString = String.Join("/",BaseAddress ,actualAddress); |
257 |
var uri = new Uri(uriString); |
258 |
var request = GetWebRequest(uri); |
259 |
request.Method = method; |
260 |
if (ResponseHeaders!=null) |
261 |
ResponseHeaders.Clear(); |
262 |
|
263 |
TraceStart(method, uriString); |
264 |
if (method == "PUT") |
265 |
request.ContentLength = 0; |
266 |
var response = (HttpWebResponse)GetWebResponse(request); |
267 |
StatusCode = response.StatusCode; |
268 |
StatusDescription = response.StatusDescription; |
269 |
|
270 |
|
271 |
return 0; |
272 |
}, actualRetries); |
273 |
|
274 |
try |
275 |
{ |
276 |
task.Wait(); |
277 |
} |
278 |
catch (AggregateException ex) |
279 |
{ |
280 |
var exc = ex.InnerException; |
281 |
if (exc is RetryException) |
282 |
{ |
283 |
Log.ErrorFormat("[{0}] RETRY FAILED for {1} after {2} retries",method,address,retries); |
284 |
} |
285 |
else |
286 |
{ |
287 |
Log.ErrorFormat("[{0}] FAILED for {1} with \n{2}", method, address, exc); |
288 |
} |
289 |
throw exc; |
290 |
|
291 |
} |
292 |
catch(Exception ex) |
293 |
{ |
294 |
Log.ErrorFormat("[{0}] FAILED for {1} with \n{2}", method, address, ex); |
295 |
throw; |
296 |
} |
297 |
} |
298 |
|
299 |
private static void TraceStart(string method, string actualAddress) |
300 |
{ |
301 |
Log.InfoFormat("[{0}] {1} {2}", method, DateTime.Now, actualAddress); |
302 |
} |
303 |
|
304 |
private string GetActualAddress(string address) |
305 |
{ |
306 |
if (Parameters.Count == 0) |
307 |
return address; |
308 |
var addressBuilder=new StringBuilder(address); |
309 |
|
310 |
bool isFirst = true; |
311 |
foreach (var parameter in Parameters) |
312 |
{ |
313 |
if(isFirst) |
314 |
addressBuilder.AppendFormat("?{0}={1}", parameter.Key, parameter.Value); |
315 |
else |
316 |
addressBuilder.AppendFormat("&{0}={1}", parameter.Key, parameter.Value); |
317 |
isFirst = false; |
318 |
} |
319 |
return addressBuilder.ToString(); |
320 |
} |
321 |
|
322 |
public string DownloadStringWithRetry(Uri address,int retries=0) |
323 |
{ |
324 |
if (address == null) |
325 |
throw new ArgumentNullException("address"); |
326 |
|
327 |
var actualRetries = (retries == 0) ? Retries : retries; |
328 |
var task = Retry(() => |
329 |
{ |
330 |
var content = base.DownloadString(address); |
331 |
|
332 |
if (StatusCode == HttpStatusCode.NoContent) |
333 |
return String.Empty; |
334 |
return content; |
335 |
|
336 |
}, actualRetries); |
337 |
|
338 |
var result = task.Result; |
339 |
return result; |
340 |
} |
341 |
|
342 |
|
343 |
/// <summary> |
344 |
/// Copies headers from another RestClient |
345 |
/// </summary> |
346 |
/// <param name="source">The RestClient from which the headers are copied</param> |
347 |
public void CopyHeaders(RestClient source) |
348 |
{ |
349 |
if (source == null) |
350 |
throw new ArgumentNullException("source", "source can't be null"); |
351 |
Contract.EndContractBlock(); |
352 |
//The Headers getter initializes the property, it is never null |
353 |
Contract.Assume(Headers!=null); |
354 |
|
355 |
CopyHeaders(source.Headers,Headers); |
356 |
} |
357 |
|
358 |
/// <summary> |
359 |
/// Copies headers from one header collection to another |
360 |
/// </summary> |
361 |
/// <param name="source">The source collection from which the headers are copied</param> |
362 |
/// <param name="target">The target collection to which the headers are copied</param> |
363 |
public static void CopyHeaders(WebHeaderCollection source,WebHeaderCollection target) |
364 |
{ |
365 |
if (source == null) |
366 |
throw new ArgumentNullException("source", "source can't be null"); |
367 |
if (target == null) |
368 |
throw new ArgumentNullException("target", "target can't be null"); |
369 |
Contract.EndContractBlock(); |
370 |
|
371 |
for (int i = 0; i < source.Count; i++) |
372 |
{ |
373 |
target.Add(source.GetKey(i), source[i]); |
374 |
} |
375 |
} |
376 |
|
377 |
public void AssertStatusOK(string message) |
378 |
{ |
379 |
if (StatusCode >= HttpStatusCode.BadRequest) |
380 |
throw new WebException(String.Format("{0} with code {1} - {2}", message, StatusCode, StatusDescription)); |
381 |
} |
382 |
|
383 |
|
384 |
private Task<T> Retry<T>(Func<T> original, int retryCount, TaskCompletionSource<T> tcs = null) |
385 |
{ |
386 |
if (original==null) |
387 |
throw new ArgumentNullException("original"); |
388 |
Contract.EndContractBlock(); |
389 |
|
390 |
if (tcs == null) |
391 |
tcs = new TaskCompletionSource<T>(); |
392 |
Task.Factory.StartNew(original).ContinueWith(_original => |
393 |
{ |
394 |
if (!_original.IsFaulted) |
395 |
tcs.SetFromTask(_original); |
396 |
else |
397 |
{ |
398 |
var e = _original.Exception.InnerException; |
399 |
var we = (e as WebException); |
400 |
if (we==null) |
401 |
tcs.SetException(e); |
402 |
else |
403 |
{ |
404 |
var statusCode = GetStatusCode(we); |
405 |
|
406 |
//Return null for 404 |
407 |
if (statusCode == HttpStatusCode.NotFound) |
408 |
tcs.SetResult(default(T)); |
409 |
//Retry for timeouts and service unavailable |
410 |
else if (we.Status == WebExceptionStatus.Timeout || |
411 |
(we.Status == WebExceptionStatus.ProtocolError && statusCode == HttpStatusCode.ServiceUnavailable)) |
412 |
{ |
413 |
TimedOut = true; |
414 |
if (retryCount == 0) |
415 |
{ |
416 |
Log.ErrorFormat("[ERROR] Timed out too many times. \n{0}\n",e); |
417 |
tcs.SetException(new RetryException("Timed out too many times.", e)); |
418 |
} |
419 |
else |
420 |
{ |
421 |
Log.ErrorFormat( |
422 |
"[RETRY] Timed out after {0} ms. Will retry {1} more times\n{2}", Timeout, |
423 |
retryCount, e); |
424 |
Retry(original, retryCount - 1, tcs); |
425 |
} |
426 |
} |
427 |
else |
428 |
tcs.SetException(e); |
429 |
} |
430 |
}; |
431 |
}); |
432 |
return tcs.Task; |
433 |
} |
434 |
|
435 |
private HttpStatusCode GetStatusCode(WebException we) |
436 |
{ |
437 |
if (we==null) |
438 |
throw new ArgumentNullException("we"); |
439 |
var statusCode = HttpStatusCode.RequestTimeout; |
440 |
if (we.Response != null) |
441 |
{ |
442 |
statusCode = ((HttpWebResponse) we.Response).StatusCode; |
443 |
this.StatusCode = statusCode; |
444 |
} |
445 |
return statusCode; |
446 |
} |
447 |
|
448 |
public UriBuilder GetAddressBuilder(string container, string objectName) |
449 |
{ |
450 |
var builder = new UriBuilder(String.Join("/", BaseAddress, container, objectName)); |
451 |
return builder; |
452 |
} |
453 |
} |
454 |
|
455 |
public class RetryException:Exception |
456 |
{ |
457 |
public RetryException() |
458 |
:base() |
459 |
{ |
460 |
|
461 |
} |
462 |
|
463 |
public RetryException(string message) |
464 |
:base(message) |
465 |
{ |
466 |
|
467 |
} |
468 |
|
469 |
public RetryException(string message,Exception innerException) |
470 |
:base(message,innerException) |
471 |
{ |
472 |
|
473 |
} |
474 |
|
475 |
public RetryException(SerializationInfo info,StreamingContext context) |
476 |
:base(info,context) |
477 |
{ |
478 |
|
479 |
} |
480 |
} |
481 |
} |