root / trunk / Pithos.Network / RestClient.cs @ 255f5f86
History | View | Annotate | Download (19.6 kB)
1 |
#region |
---|---|
2 |
/* ----------------------------------------------------------------------- |
3 |
* <copyright file="RestClient.cs" company="GRNet"> |
4 |
* |
5 |
* Copyright 2011-2012 GRNET S.A. All rights reserved. |
6 |
* |
7 |
* Redistribution and use in source and binary forms, with or |
8 |
* without modification, are permitted provided that the following |
9 |
* conditions are met: |
10 |
* |
11 |
* 1. Redistributions of source code must retain the above |
12 |
* copyright notice, this list of conditions and the following |
13 |
* disclaimer. |
14 |
* |
15 |
* 2. Redistributions in binary form must reproduce the above |
16 |
* copyright notice, this list of conditions and the following |
17 |
* disclaimer in the documentation and/or other materials |
18 |
* provided with the distribution. |
19 |
* |
20 |
* |
21 |
* THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS |
22 |
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
23 |
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
24 |
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR |
25 |
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
26 |
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
27 |
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
28 |
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
29 |
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
30 |
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
31 |
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
32 |
* POSSIBILITY OF SUCH DAMAGE. |
33 |
* |
34 |
* The views and conclusions contained in the software and |
35 |
* documentation are those of the authors and should not be |
36 |
* interpreted as representing official policies, either expressed |
37 |
* or implied, of GRNET S.A. |
38 |
* </copyright> |
39 |
* ----------------------------------------------------------------------- |
40 |
*/ |
41 |
#endregion |
42 |
using System.Collections.Specialized; |
43 |
using System.Diagnostics; |
44 |
using System.Diagnostics.Contracts; |
45 |
using System.IO; |
46 |
using System.Net; |
47 |
using System.Runtime.Serialization; |
48 |
using System.Threading.Tasks; |
49 |
using log4net; |
50 |
|
51 |
|
52 |
namespace Pithos.Network |
53 |
{ |
54 |
using System; |
55 |
using System.Collections.Generic; |
56 |
using System.Linq; |
57 |
using System.Text; |
58 |
|
59 |
/// <summary> |
60 |
/// TODO: Update summary. |
61 |
/// </summary> |
62 |
public class RestClient:WebClient |
63 |
{ |
64 |
public int Timeout { get; set; } |
65 |
|
66 |
public bool TimedOut { get; set; } |
67 |
|
68 |
public HttpStatusCode StatusCode { get; private set; } |
69 |
|
70 |
public string StatusDescription { get; set; } |
71 |
|
72 |
public long? RangeFrom { get; set; } |
73 |
public long? RangeTo { get; set; } |
74 |
|
75 |
public int Retries { get; set; } |
76 |
|
77 |
private readonly Dictionary<string, string> _parameters=new Dictionary<string, string>(); |
78 |
public Dictionary<string, string> Parameters |
79 |
{ |
80 |
get |
81 |
{ |
82 |
Contract.Ensures(_parameters!=null); |
83 |
return _parameters; |
84 |
} |
85 |
} |
86 |
|
87 |
private static readonly ILog Log = LogManager.GetLogger("RestClient"); |
88 |
|
89 |
|
90 |
[ContractInvariantMethod] |
91 |
private void Invariants() |
92 |
{ |
93 |
Contract.Invariant(Headers!=null); |
94 |
} |
95 |
|
96 |
public RestClient():base() |
97 |
{ |
98 |
|
99 |
} |
100 |
|
101 |
|
102 |
public RestClient(RestClient other) |
103 |
: base() |
104 |
{ |
105 |
if (other==null) |
106 |
throw new ArgumentNullException("other"); |
107 |
Contract.EndContractBlock(); |
108 |
|
109 |
CopyHeaders(other); |
110 |
Timeout = other.Timeout; |
111 |
Retries = other.Retries; |
112 |
BaseAddress = other.BaseAddress; |
113 |
|
114 |
foreach (var parameter in other.Parameters) |
115 |
{ |
116 |
Parameters.Add(parameter.Key,parameter.Value); |
117 |
} |
118 |
|
119 |
this.Proxy = other.Proxy; |
120 |
} |
121 |
|
122 |
|
123 |
protected override WebRequest GetWebRequest(Uri address) |
124 |
{ |
125 |
TimedOut = false; |
126 |
var webRequest = base.GetWebRequest(address); |
127 |
var request = (HttpWebRequest)webRequest; |
128 |
request.ServicePoint.ConnectionLimit = 50; |
129 |
if (IfModifiedSince.HasValue) |
130 |
request.IfModifiedSince = IfModifiedSince.Value; |
131 |
request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip; |
132 |
if(Timeout>0) |
133 |
request.Timeout = Timeout; |
134 |
|
135 |
if (RangeFrom.HasValue) |
136 |
{ |
137 |
if (RangeTo.HasValue) |
138 |
request.AddRange(RangeFrom.Value, RangeTo.Value); |
139 |
else |
140 |
request.AddRange(RangeFrom.Value); |
141 |
} |
142 |
return request; |
143 |
} |
144 |
|
145 |
public DateTime? IfModifiedSince { get; set; } |
146 |
|
147 |
//Asynchronous version |
148 |
protected override WebResponse GetWebResponse(WebRequest request, IAsyncResult result) |
149 |
{ |
150 |
Log.InfoFormat("ASYNC [{0}] {1}",request.Method, request.RequestUri); |
151 |
HttpWebResponse response = null; |
152 |
|
153 |
try |
154 |
{ |
155 |
response = (HttpWebResponse)base.GetWebResponse(request, result); |
156 |
} |
157 |
catch (WebException exc) |
158 |
{ |
159 |
if (!TryGetResponse(exc, out response)) |
160 |
throw; |
161 |
} |
162 |
|
163 |
StatusCode = response.StatusCode; |
164 |
LastModified = response.LastModified; |
165 |
StatusDescription = response.StatusDescription; |
166 |
return response; |
167 |
|
168 |
} |
169 |
|
170 |
|
171 |
//Synchronous version |
172 |
protected override WebResponse GetWebResponse(WebRequest request) |
173 |
{ |
174 |
HttpWebResponse response = null; |
175 |
try |
176 |
{ |
177 |
response = (HttpWebResponse)base.GetWebResponse(request); |
178 |
} |
179 |
catch (WebException exc) |
180 |
{ |
181 |
if (!TryGetResponse(exc, out response)) |
182 |
throw; |
183 |
} |
184 |
|
185 |
StatusCode = response.StatusCode; |
186 |
LastModified = response.LastModified; |
187 |
StatusDescription = response.StatusDescription; |
188 |
return response; |
189 |
} |
190 |
|
191 |
private bool TryGetResponse(WebException exc, out HttpWebResponse response) |
192 |
{ |
193 |
response = null; |
194 |
//Fail on empty response |
195 |
if (exc.Response == null) |
196 |
return false; |
197 |
|
198 |
response = (exc.Response as HttpWebResponse); |
199 |
//Succeed on allowed status codes |
200 |
if (AllowedStatusCodes.Contains(response.StatusCode)) |
201 |
return true; |
202 |
|
203 |
//Does the response have any content to log? |
204 |
if (exc.Response.ContentLength > 0) |
205 |
{ |
206 |
var content = LogContent(exc.Response); |
207 |
Log.ErrorFormat(content); |
208 |
} |
209 |
return false; |
210 |
} |
211 |
|
212 |
private readonly List<HttpStatusCode> _allowedStatusCodes=new List<HttpStatusCode>{HttpStatusCode.NotModified}; |
213 |
|
214 |
public List<HttpStatusCode> AllowedStatusCodes |
215 |
{ |
216 |
get |
217 |
{ |
218 |
return _allowedStatusCodes; |
219 |
} |
220 |
} |
221 |
|
222 |
public DateTime LastModified { get; private set; } |
223 |
|
224 |
private static string LogContent(WebResponse webResponse) |
225 |
{ |
226 |
if (webResponse == null) |
227 |
throw new ArgumentNullException("webResponse"); |
228 |
Contract.EndContractBlock(); |
229 |
|
230 |
//The response stream must be copied to avoid affecting other code by disposing of the |
231 |
//original response stream. |
232 |
var stream = webResponse.GetResponseStream(); |
233 |
using(var memStream=new MemoryStream()) |
234 |
using (var reader = new StreamReader(memStream)) |
235 |
{ |
236 |
stream.CopyTo(memStream); |
237 |
string content = reader.ReadToEnd(); |
238 |
|
239 |
stream.Seek(0,SeekOrigin.Begin); |
240 |
return content; |
241 |
} |
242 |
} |
243 |
|
244 |
public string DownloadStringWithRetry(string address,int retries=0) |
245 |
{ |
246 |
|
247 |
if (address == null) |
248 |
throw new ArgumentNullException("address"); |
249 |
|
250 |
var actualAddress = GetActualAddress(address); |
251 |
|
252 |
TraceStart("GET",actualAddress); |
253 |
|
254 |
var actualRetries = (retries == 0) ? Retries : retries; |
255 |
|
256 |
var uriString = String.Join("/", BaseAddress.TrimEnd('/'), actualAddress); |
257 |
|
258 |
var task = Retry(() => |
259 |
{ |
260 |
var content = base.DownloadString(uriString); |
261 |
|
262 |
if (StatusCode == HttpStatusCode.NoContent) |
263 |
return String.Empty; |
264 |
return content; |
265 |
|
266 |
}, actualRetries); |
267 |
|
268 |
try |
269 |
{ |
270 |
var result = task.Result; |
271 |
return result; |
272 |
|
273 |
} |
274 |
catch (AggregateException exc) |
275 |
{ |
276 |
//If the task fails, propagate the original exception |
277 |
if (exc.InnerException!=null) |
278 |
throw exc.InnerException; |
279 |
throw; |
280 |
} |
281 |
} |
282 |
|
283 |
public void Head(string address,int retries=0) |
284 |
{ |
285 |
AllowedStatusCodes.Add(HttpStatusCode.NotFound); |
286 |
RetryWithoutContent(address, retries, "HEAD"); |
287 |
} |
288 |
|
289 |
public void PutWithRetry(string address, int retries = 0) |
290 |
{ |
291 |
RetryWithoutContent(address, retries, "PUT"); |
292 |
} |
293 |
|
294 |
public void DeleteWithRetry(string address,int retries=0) |
295 |
{ |
296 |
RetryWithoutContent(address, retries, "DELETE"); |
297 |
} |
298 |
|
299 |
public string GetHeaderValue(string headerName,bool optional=false) |
300 |
{ |
301 |
if (this.ResponseHeaders==null) |
302 |
throw new InvalidOperationException("ResponseHeaders are null"); |
303 |
Contract.EndContractBlock(); |
304 |
|
305 |
var values=this.ResponseHeaders.GetValues(headerName); |
306 |
if (values != null) |
307 |
return values[0]; |
308 |
|
309 |
if (optional) |
310 |
return null; |
311 |
//A required header was not found |
312 |
throw new WebException(String.Format("The {0} header is missing", headerName)); |
313 |
} |
314 |
|
315 |
public void SetNonEmptyHeaderValue(string headerName, string value) |
316 |
{ |
317 |
if (String.IsNullOrWhiteSpace(value)) |
318 |
return; |
319 |
Headers.Add(headerName,value); |
320 |
} |
321 |
|
322 |
private void RetryWithoutContent(string address, int retries, string method) |
323 |
{ |
324 |
if (address == null) |
325 |
throw new ArgumentNullException("address"); |
326 |
|
327 |
var actualAddress = GetActualAddress(address); |
328 |
var actualRetries = (retries == 0) ? Retries : retries; |
329 |
|
330 |
var task = Retry(() => |
331 |
{ |
332 |
var uriString = String.Join("/",BaseAddress ,actualAddress); |
333 |
var uri = new Uri(uriString); |
334 |
var request = GetWebRequest(uri); |
335 |
request.Method = method; |
336 |
if (ResponseHeaders!=null) |
337 |
ResponseHeaders.Clear(); |
338 |
|
339 |
TraceStart(method, uriString); |
340 |
if (method == "PUT") |
341 |
request.ContentLength = 0; |
342 |
|
343 |
//Have to use try/finally instead of using here, because WebClient needs a valid WebResponse object |
344 |
//in order to return response headers |
345 |
var response = (HttpWebResponse)GetWebResponse(request); |
346 |
try |
347 |
{ |
348 |
LastModified = response.LastModified; |
349 |
StatusCode = response.StatusCode; |
350 |
StatusDescription = response.StatusDescription; |
351 |
} |
352 |
finally |
353 |
{ |
354 |
response.Close(); |
355 |
} |
356 |
|
357 |
|
358 |
return 0; |
359 |
}, actualRetries); |
360 |
|
361 |
try |
362 |
{ |
363 |
task.Wait(); |
364 |
} |
365 |
catch (AggregateException ex) |
366 |
{ |
367 |
var exc = ex.InnerException; |
368 |
if (exc is RetryException) |
369 |
{ |
370 |
Log.ErrorFormat("[{0}] RETRY FAILED for {1} after {2} retries",method,address,retries); |
371 |
} |
372 |
else |
373 |
{ |
374 |
Log.ErrorFormat("[{0}] FAILED for {1} with \n{2}", method, address, exc); |
375 |
} |
376 |
throw exc; |
377 |
|
378 |
} |
379 |
catch(Exception ex) |
380 |
{ |
381 |
Log.ErrorFormat("[{0}] FAILED for {1} with \n{2}", method, address, ex); |
382 |
throw; |
383 |
} |
384 |
} |
385 |
|
386 |
private static void TraceStart(string method, string actualAddress) |
387 |
{ |
388 |
Log.InfoFormat("[{0}] {1} {2}", method, DateTime.Now, actualAddress); |
389 |
} |
390 |
|
391 |
private string GetActualAddress(string address) |
392 |
{ |
393 |
if (Parameters.Count == 0) |
394 |
return address; |
395 |
var addressBuilder=new StringBuilder(address); |
396 |
|
397 |
bool isFirst = true; |
398 |
foreach (var parameter in Parameters) |
399 |
{ |
400 |
if(isFirst) |
401 |
addressBuilder.AppendFormat("?{0}={1}", parameter.Key, parameter.Value); |
402 |
else |
403 |
addressBuilder.AppendFormat("&{0}={1}", parameter.Key, parameter.Value); |
404 |
isFirst = false; |
405 |
} |
406 |
return addressBuilder.ToString(); |
407 |
} |
408 |
|
409 |
public string DownloadStringWithRetry(Uri address,int retries=0) |
410 |
{ |
411 |
if (address == null) |
412 |
throw new ArgumentNullException("address"); |
413 |
|
414 |
var actualRetries = (retries == 0) ? Retries : retries; |
415 |
var task = Retry(() => |
416 |
{ |
417 |
var content = base.DownloadString(address); |
418 |
|
419 |
if (StatusCode == HttpStatusCode.NoContent) |
420 |
return String.Empty; |
421 |
return content; |
422 |
|
423 |
}, actualRetries); |
424 |
|
425 |
var result = task.Result; |
426 |
return result; |
427 |
} |
428 |
|
429 |
|
430 |
/// <summary> |
431 |
/// Copies headers from another RestClient |
432 |
/// </summary> |
433 |
/// <param name="source">The RestClient from which the headers are copied</param> |
434 |
public void CopyHeaders(RestClient source) |
435 |
{ |
436 |
if (source == null) |
437 |
throw new ArgumentNullException("source", "source can't be null"); |
438 |
Contract.EndContractBlock(); |
439 |
//The Headers getter initializes the property, it is never null |
440 |
Contract.Assume(Headers!=null); |
441 |
|
442 |
CopyHeaders(source.Headers,Headers); |
443 |
} |
444 |
|
445 |
/// <summary> |
446 |
/// Copies headers from one header collection to another |
447 |
/// </summary> |
448 |
/// <param name="source">The source collection from which the headers are copied</param> |
449 |
/// <param name="target">The target collection to which the headers are copied</param> |
450 |
public static void CopyHeaders(WebHeaderCollection source,WebHeaderCollection target) |
451 |
{ |
452 |
if (source == null) |
453 |
throw new ArgumentNullException("source", "source can't be null"); |
454 |
if (target == null) |
455 |
throw new ArgumentNullException("target", "target can't be null"); |
456 |
Contract.EndContractBlock(); |
457 |
|
458 |
for (int i = 0; i < source.Count; i++) |
459 |
{ |
460 |
target.Add(source.GetKey(i), source[i]); |
461 |
} |
462 |
} |
463 |
|
464 |
public void AssertStatusOK(string message) |
465 |
{ |
466 |
if (StatusCode >= HttpStatusCode.BadRequest) |
467 |
throw new WebException(String.Format("{0} with code {1} - {2}", message, StatusCode, StatusDescription)); |
468 |
} |
469 |
|
470 |
|
471 |
private Task<T> Retry<T>(Func<T> original, int retryCount, TaskCompletionSource<T> tcs = null) |
472 |
{ |
473 |
if (original==null) |
474 |
throw new ArgumentNullException("original"); |
475 |
Contract.EndContractBlock(); |
476 |
|
477 |
if (tcs == null) |
478 |
tcs = new TaskCompletionSource<T>(); |
479 |
Task.Factory.StartNew(original).ContinueWith(_original => |
480 |
{ |
481 |
if (!_original.IsFaulted) |
482 |
tcs.SetFromTask(_original); |
483 |
else |
484 |
{ |
485 |
var e = _original.Exception.InnerException; |
486 |
var we = (e as WebException); |
487 |
if (we==null) |
488 |
tcs.SetException(e); |
489 |
else |
490 |
{ |
491 |
var statusCode = GetStatusCode(we); |
492 |
|
493 |
//Return null for 404 |
494 |
if (statusCode == HttpStatusCode.NotFound) |
495 |
tcs.SetResult(default(T)); |
496 |
//Retry for timeouts and service unavailable |
497 |
else if (we.Status == WebExceptionStatus.Timeout || |
498 |
(we.Status == WebExceptionStatus.ProtocolError && statusCode == HttpStatusCode.ServiceUnavailable)) |
499 |
{ |
500 |
TimedOut = true; |
501 |
if (retryCount == 0) |
502 |
{ |
503 |
Log.ErrorFormat("[ERROR] Timed out too many times. \n{0}\n",e); |
504 |
tcs.SetException(new RetryException("Timed out too many times.", e)); |
505 |
} |
506 |
else |
507 |
{ |
508 |
Log.ErrorFormat( |
509 |
"[RETRY] Timed out after {0} ms. Will retry {1} more times\n{2}", Timeout, |
510 |
retryCount, e); |
511 |
Retry(original, retryCount - 1, tcs); |
512 |
} |
513 |
} |
514 |
else |
515 |
tcs.SetException(e); |
516 |
} |
517 |
}; |
518 |
}); |
519 |
return tcs.Task; |
520 |
} |
521 |
|
522 |
private HttpStatusCode GetStatusCode(WebException we) |
523 |
{ |
524 |
if (we==null) |
525 |
throw new ArgumentNullException("we"); |
526 |
var statusCode = HttpStatusCode.RequestTimeout; |
527 |
if (we.Response != null) |
528 |
{ |
529 |
statusCode = ((HttpWebResponse) we.Response).StatusCode; |
530 |
this.StatusCode = statusCode; |
531 |
} |
532 |
return statusCode; |
533 |
} |
534 |
|
535 |
public UriBuilder GetAddressBuilder(string container, string objectName) |
536 |
{ |
537 |
var builder = new UriBuilder(String.Join("/", BaseAddress, container, objectName)); |
538 |
return builder; |
539 |
} |
540 |
|
541 |
public Dictionary<string, string> GetMeta(string metaPrefix) |
542 |
{ |
543 |
if (String.IsNullOrWhiteSpace(metaPrefix)) |
544 |
throw new ArgumentNullException("metaPrefix"); |
545 |
Contract.EndContractBlock(); |
546 |
|
547 |
var keys = ResponseHeaders.AllKeys.AsQueryable(); |
548 |
var dict = (from key in keys |
549 |
where key.StartsWith(metaPrefix) |
550 |
let name = key.Substring(metaPrefix.Length) |
551 |
select new { Name = name, Value = ResponseHeaders[key] }) |
552 |
.ToDictionary(t => t.Name, t => t.Value); |
553 |
return dict; |
554 |
} |
555 |
} |
556 |
|
557 |
public class RetryException:Exception |
558 |
{ |
559 |
public RetryException() |
560 |
:base() |
561 |
{ |
562 |
|
563 |
} |
564 |
|
565 |
public RetryException(string message) |
566 |
:base(message) |
567 |
{ |
568 |
|
569 |
} |
570 |
|
571 |
public RetryException(string message,Exception innerException) |
572 |
:base(message,innerException) |
573 |
{ |
574 |
|
575 |
} |
576 |
|
577 |
public RetryException(SerializationInfo info,StreamingContext context) |
578 |
:base(info,context) |
579 |
{ |
580 |
|
581 |
} |
582 |
} |
583 |
} |