arq_restore/cocoastack/aws/AWSQueryRequest.m

/*
 Copyright (c) 2009-2017, Haystack Software LLC https://www.arqbackup.com
 
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
 
 * Redistributions of source code must retain the above copyright
 notice, this list of conditions and the following disclaimer.
 
 * Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
 
 * Neither the names of PhotoMinds LLC or Haystack Software, nor the names of
 their contributors may be used to endorse or promote products derived from
 this software without specific prior written permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */



#import "AWSQueryRequest.h"
#import "AWSQueryResponse.h"
#import "HTTPConnectionFactory.h"
#import "HTTPConnection.h"
#import "InputStream.h"
#import "HTTP.h"
#import "AWSQueryError.h"


#define INITIAL_RETRY_SLEEP (0.5)
#define RETRY_SLEEP_GROWTH_FACTOR (1.5)
#define MAX_RETRY_SLEEP (5.0)


@interface AWSQueryRequest ()
- (AWSQueryResponse *)executeOnce:(NSError **)error;
@end


@implementation AWSQueryRequest
- (id)initWithMethod:(NSString *)theMethod url:(NSURL *)theURL retryOnTransientError:(BOOL)theRetryOnTransientError {
    if (self = [super init]) {
        method = [theMethod retain];
        url = [theURL retain];
        retryOnTransientError = theRetryOnTransientError;
    }
    return self;
}
- (void)dealloc {
    [method release];
    [url release];
    [super dealloc];
}

- (NSString *)errorDomain {
    return @"AWSQueryRequestErrorDomain";
}
- (AWSQueryResponse *)execute:(NSError **)error {
    NSAutoreleasePool *pool = nil;
    NSTimeInterval sleepTime = INITIAL_RETRY_SLEEP;
    AWSQueryResponse *theResponse = nil;
    NSError *myError = nil;
    for (;;) {
        [pool drain];
        pool = [[NSAutoreleasePool alloc] init];
        BOOL transientError = NO;
        BOOL needSleep = NO;
        myError = nil;
        theResponse = [self executeOnce:&myError];
        if (theResponse != nil) {
            break;
        }
        if ([myError isErrorWithDomain:[self errorDomain] code:ERROR_NOT_FOUND]) {
            break;
        } else if ([[[myError userInfo] objectForKey:@"HTTPStatusCode"] intValue] == HTTP_INTERNAL_SERVER_ERROR) {
            transientError = YES;
        } else if ([myError isConnectionResetError]) {
            transientError = YES;
        } else if (retryOnTransientError && [myError isErrorWithDomain:[self errorDomain] code:HTTP_SERVICE_NOT_AVAILABLE]) {
            // Sometimes SQS returns a 503 error, and we're supposed to retry in that case.
            transientError = YES;
            needSleep = YES;
        } else if (retryOnTransientError && [myError isTransientError]) {
            transientError = YES;
            needSleep = YES;
        } else {
            HSLogError(@"%@ %@: %@", method, url, myError);
            break;
        }
        
        if (transientError) {
            HSLogDetail(@"retrying %@ %@: %@", method, url, myError);
        }
        if (needSleep) {
            [NSThread sleepForTimeInterval:sleepTime];
            sleepTime *= RETRY_SLEEP_GROWTH_FACTOR;
            if (sleepTime > MAX_RETRY_SLEEP) {
                sleepTime = MAX_RETRY_SLEEP;
            }
        }
    }
    [theResponse retain];
    [myError retain];
    [pool drain];
    [theResponse autorelease];
    [myError autorelease];
    if (error != NULL) { *error = myError; }
    return theResponse;
}


#pragma mark internal
- (AWSQueryResponse *)executeOnce:(NSError **)error {
    id <HTTPConnection> conn = [[[HTTPConnectionFactory theFactory] newHTTPConnectionToURL:url method:method dataTransferDelegate:nil] autorelease];
    if (conn == nil) {
        return nil;
    }
    [conn setRequestHostHeader];
    HSLogDebug(@"%@ %@", method, url);
    NSData *responseData = [conn executeRequest:error];
    if (responseData == nil) {
        return nil;
    }
    int code = [conn responseCode];
    if (code >= 200 && code <= 299) {
        HSLogDebug(@"HTTP %d; returning response length=%lu", code, (unsigned long)[responseData length]);
        AWSQueryResponse *response = [[[AWSQueryResponse alloc] initWithCode:code headers:[conn responseHeaders] body:responseData] autorelease];
        return response;
    }
    
    if (code == HTTP_NOT_FOUND) {
        SETNSERROR([self errorDomain], ERROR_NOT_FOUND, @"%@ not found", url);
        HSLogDebug(@"returning not-found error");
        return nil;
    }
    if (code == HTTP_METHOD_NOT_ALLOWED) {
        HSLogError(@"%@ 405 error", url);
        SETNSERROR([self errorDomain], ERROR_RRS_NOT_FOUND, @"%@ 405 error", url);
    }
    AWSQueryError *queryError = [[[AWSQueryError alloc] initWithDomain:[self errorDomain] httpStatusCode:code responseBody:responseData] autorelease];
    NSError *myError = [queryError nsError];
    HSLogDebug(@"%@ %@ error: %@", method, conn, myError);
    if (error != NULL) {
        *error = myError;
    }
    return nil;
}
@end