arq_restore/s3/S3Request.m

/*
 Copyright (c) 2009, Stefan Reitshamer http://www.haystacksoftware.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 "S3Request.h"
#import "HTTP.h"
#import "HTTPConnection.h"
#import "HTTPConnection_S3.h"
#import "ServerBlob.h"
#import "Blob.h"
#import "S3Service.h"
#import "NSXMLNode_extra.h"
#import "SetNSError.h"
#import "CFStreamPair.h"
#import "RegexKitLite.h"

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

@interface S3Request (internal)
- (ServerBlob *)newServerBlobOnce:(NSError **)error;
@end

@implementation S3Request
- (id)initWithMethod:(NSString *)theMethod path:(NSString *)thePath queryString:(NSString *)theQueryString authorizationProvider:(S3AuthorizationProvider *)theSAP useSSL:(BOOL)ssl retryOnNetworkError:(BOOL)retry {
    if (self = [super init]) {
        method = [theMethod copy];
        path = [thePath copy];
        NSRange s3BucketNameRange = [path rangeOfRegex:@"^/([^/]+)" capture:1];
        if (s3BucketNameRange.location != NSNotFound) {
            s3BucketName = [path substringWithRange:s3BucketNameRange];
        }
        queryString = [theQueryString copy];
        sap = [theSAP retain];
        withSSL = ssl;
        retryOnNetworkError = retry;
    }
    return self;
}
- (void)dealloc {
    [method release];
    [path release];
    [queryString release];
    [sap release];
    [virtualHost release];
    [virtualPath release];
    [super dealloc];
}
- (ServerBlob *)newServerBlob:(NSError **)error {
    [virtualHost release];
    virtualHost = nil;
    [virtualPath release];
    virtualPath = nil;
    if ([path isEqualToString:@"/"]) {
        // List-bucket request.
        virtualHost = [@"s3.amazonaws.com" retain];
        virtualPath = [path retain];
    } else {
        NSString *pattern = @"^/([^/]+)(.+)$";
        NSRange s3BucketRange = [path rangeOfRegex:pattern capture:1];
        if (s3BucketRange.location == NSNotFound) {
            SETNSERROR(@"S3ServiceErrorDomain", -1, @"invalid path-style path -- missing s3 bucket name");
            return nil;
        }
        NSRange pathRange = [path rangeOfRegex:pattern capture:2];
        if (pathRange.location == NSNotFound) {
            SETNSERROR(@"S3ServiceErrorDomain", -1, @"invalid path-style path -- missing path");
            return nil;
        }
        virtualHost = [[[path substringWithRange:s3BucketRange] stringByAppendingString:@".s3.amazonaws.com"] retain];
        virtualPath = [[path substringWithRange:pathRange] retain];
    }
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSTimeInterval sleepTime = INITIAL_RETRY_SLEEP;
    ServerBlob *sb = nil;
    NSError *myError = nil;
    for (;;) {
        myError = nil;
        NSAutoreleasePool *pool2 = [[NSAutoreleasePool alloc] init];
        sb = [self newServerBlobOnce:&myError];
        [myError retain];
        [pool2 drain];
        [myError autorelease];
        if (sb != nil) {
            break;
        }
        BOOL needSleep = NO;
        if ([[myError domain] isEqualToString:[S3Service serverErrorDomain]]) {
            NSString *amazonErrorCode = [[myError userInfo] objectForKey:@"Code"];
            if ([myError code] == HTTP_INTERNAL_SERVER_ERROR) {
                HSLogInfo(@"S3 returned %u; retrying", HTTP_INTERNAL_SERVER_ERROR);
                needSleep = YES;
            } else if ([myError code] == HTTP_BAD_REQUEST && [amazonErrorCode isEqualToString:@"RequestTimeout"]) {
                HSLogInfo(@"s3 RequestTimeout; retrying");
            } else if ([myError code] == HTTP_SERVICE_NOT_AVAILABLE) {
                HSLogInfo(@"S3 returned @u; retrying", HTTP_SERVICE_NOT_AVAILABLE);
                needSleep = YES;
            } else if ([myError code] == HTTP_MOVED_TEMPORARILY) {
                [virtualHost release];
                virtualHost = [[[myError userInfo] objectForKey:@"Endpoint"] copy];
                HSLogDebug(@"S3 redirect to %@", virtualHost);
            } else {
                if ([myError code] != HTTP_NOT_FOUND) {
                    HSLogError(@"error getting %@: %@", virtualPath, [myError localizedDescription]);
                }
                break;
            }
        } else if ([[myError domain] isEqualToString:[CFStreamPair errorDomain]] && retryOnNetworkError) {
            HSLogDebug(@"network error (retrying): %@", [myError localizedDescription]);
            needSleep = YES;
        } else {
            break;
        }
        if (needSleep) {
            [NSThread sleepForTimeInterval:sleepTime];
            sleepTime *= RETRY_SLEEP_GROWTH_FACTOR;
            if (sleepTime > MAX_RETRY_SLEEP) {
                sleepTime = MAX_RETRY_SLEEP;
            }
        }
    }
    [myError retain];
    [pool drain];
    [myError autorelease];
    if (sb == nil && error != NULL) {
        NSAssert(myError != nil, @"myError must be set");
        *error = myError;
    }
    return sb;
}
@end

@implementation S3Request (internal)
- (ServerBlob *)newServerBlobOnce:(NSError **)error {
    HTTPConnection *conn = [[[HTTPConnection alloc] initWithHost:virtualHost useSSL:withSSL error:error] autorelease];
    if (conn == nil) {
        return nil;
    }
    [conn setRequestMethod:method pathInfo:[virtualPath stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding] queryString:queryString protocol:HTTP_1_1];
    [conn setRequestHostHeader];
    [conn setRFC822DateRequestHeader];
    [conn setRequestKeepAliveHeader];
    [conn setAuthorizationRequestHeaderUsingProvider:sap s3BucketName:s3BucketName];
    BOOL execRet = [conn executeRequest:error];
    if (!execRet) {
        return nil;
    }
    ServerBlob *ret = nil;
    int code = [conn responseCode];
    if (code >= 200 && code <= 299) {
        id <InputStream> bodyStream = [conn newResponseBodyStream:error];
        if (bodyStream == nil) {
            return nil;
        }
        ret = [[ServerBlob alloc] initWithInputStream:bodyStream mimeType:[conn responseMimeType] downloadName:[conn responseDownloadName]];
        [bodyStream release];
    } else {
        if (code >= 400 && code != HTTP_NOT_FOUND) {
            HSLogDebug(@"S3 HTTP response code was %d; requesting close on connection", code);
            [conn setCloseRequested];
        }
        NSData *response = [conn slurpResponseBody:error];
        if (response == nil) {
            return nil;
        }
        NSXMLDocument *xmlDoc = [[NSXMLDocument alloc] initWithData:response options:0 error:error];
        HSLogTrace(@"%@", [xmlDoc description]);
        if (xmlDoc == nil) {
            return nil;
        }
        NSXMLElement *rootElement = [xmlDoc rootElement];
        NSArray *errorNodes = [rootElement nodesForXPath:@"//Error" error:error];
        if (errorNodes == nil) {
            [xmlDoc release];
            return nil;
        } else if ([errorNodes count] == 0) {
            HSLogWarn(@"missing Error node in S3 XML response");
            SETNSERROR([S3Service errorDomain], code, @"S3 error");
            [xmlDoc release];
            return nil;
        } else {
            if ([errorNodes count] > 1) {
                HSLogWarn(@"ignoring additional S3 errors");
            }
            NSXMLNode *errorNode = [errorNodes objectAtIndex:0];
            NSString *errorCode = [[errorNode childNodeNamed:@"Code"] stringValue];
            NSString *errorMessage = [[errorNode childNodeNamed:@"Message"] stringValue];
            if (code == HTTP_NOT_FOUND) {
                errorMessage = [NSString stringWithFormat:@"%@ not found", virtualPath];
            }
            NSString *endpoint = (code == HTTP_MOVED_TEMPORARILY) ? [[errorNode childNodeNamed:@"Endpoint"] stringValue] : nil;
            NSDictionary *userInfo = [NSDictionary dictionaryWithObjectsAndKeys:
                                      (errorCode != nil ? errorCode : @""), @"Code",
                                      (errorMessage != nil ? errorMessage : @""), @"Message",
                                      (errorMessage != nil ? errorMessage : @""), NSLocalizedDescriptionKey,
                                      (endpoint != nil ? endpoint : @""), @"Endpoint",
                                      nil];
            NSError *myError = [NSError errorWithDomain:[S3Service serverErrorDomain] code:code userInfo:userInfo];
            if (error != NULL) {
                *error = myError;
            }
        }
        [xmlDoc release];
    }
    return ret;
}
@end