C++ String::erase方法代码示例

static Http::HeaderValueCollection CanonicalizeHeaders(Http::HeaderValueCollection&& headers)
{
    Http::HeaderValueCollection canonicalHeaders;
    for (const auto& header : headers)
    {
        auto trimmedHeaderName = StringUtils::Trim(header.first.c_str());
        auto trimmedHeaderValue = StringUtils::Trim(header.second.c_str());

        //multiline gets converted to line1,line2,etc...
        auto headerMultiLine = StringUtils::SplitOnLine(trimmedHeaderValue);
        Aws::String headerValue = headerMultiLine[0];

        if (headerMultiLine.size() > 1)
        {
            for(size_t i = 1; i < headerMultiLine.size(); ++i)
            {
                headerValue += ",";
                headerValue += StringUtils::Trim(headerMultiLine[i].c_str());
            }
        }

        //duplicate spaces need to be converted to one.
        Aws::String::iterator new_end =
            std::unique(headerValue.begin(), headerValue.end(),
                [=](char lhs, char rhs) { return (lhs == rhs) && (lhs == ' '); }
        );
        headerValue.erase(new_end, headerValue.end());

        canonicalHeaders[trimmedHeaderName] = headerValue;       
    }

    return canonicalHeaders;
}

void StringUtils::Replace(Aws::String &s, const char* search, const char* replace)
{
    if(!search || !replace)
    {
        return;
    }

    size_t replaceLength = strlen(replace);
    size_t searchLength = strlen(search);

    for (std::size_t pos = 0;; pos += replaceLength)
    {
        pos = s.find(search, pos);
        if (pos == Aws::String::npos)
            break;

        s.erase(pos, searchLength);
        s.insert(pos, replace);
    }
}

bool AWSAuthV4Signer::SignRequest(Aws::Http::HttpRequest& request, bool signBody) const
{
    AWSCredentials credentials = m_credentialsProvider->GetAWSCredentials();

    //don't sign anonymous requests
    if (credentials.GetAWSAccessKeyId().empty() || credentials.GetAWSSecretKey().empty())
    {
        return true;
    }

    if (!credentials.GetSessionToken().empty())
    {
        request.SetAwsSessionToken(credentials.GetSessionToken());
    }

    Aws::String payloadHash(UNSIGNED_PAYLOAD);
    if(signBody || request.GetUri().GetScheme() != Http::Scheme::HTTPS)
    {
        payloadHash.assign(ComputePayloadHash(request));
        if (payloadHash.empty())
        {
            return false;
        }
    }
    else
    {
        AWS_LOGSTREAM_DEBUG(v4LogTag, "Note: Http payloads are not being signed. signPayloads=" << m_signPayloads
                << " http scheme=" << Http::SchemeMapper::ToString(request.GetUri().GetScheme()));
    }

    if(m_includeSha256HashHeader)
    {
        request.SetHeaderValue("x-amz-content-sha256", payloadHash);
    }

    //calculate date header to use in internal signature (this also goes into date header).
    DateTime now = GetSigningTimestamp();
    Aws::String dateHeaderValue = now.ToGmtString(LONG_DATE_FORMAT_STR);
    request.SetHeaderValue(AWS_DATE_HEADER, dateHeaderValue);

    Aws::StringStream headersStream;
    Aws::StringStream signedHeadersStream;

    for (const auto& header : CanonicalizeHeaders(request.GetHeaders()))
    {
        if(ShouldSignHeader(header.first))
        {
            headersStream << header.first.c_str() << ":" << header.second.c_str() << NEWLINE;
            signedHeadersStream << header.first.c_str() << ";";
        }
    }

    Aws::String canonicalHeadersString = headersStream.str();
    AWS_LOGSTREAM_DEBUG(v4LogTag, "Canonical Header String: " << canonicalHeadersString);

    //calculate signed headers parameter
    Aws::String signedHeadersValue = signedHeadersStream.str();
    //remove that last semi-colon
    signedHeadersValue.erase(signedHeadersValue.length() - 1);
    AWS_LOGSTREAM_DEBUG(v4LogTag, "Signed Headers value:" << signedHeadersValue);

    //generate generalized canonicalized request string.
    Aws::String canonicalRequestString = CanonicalizeRequestSigningString(request, m_urlEscapePath);

    //append v4 stuff to the canonical request string.
    canonicalRequestString.append(canonicalHeadersString);
    canonicalRequestString.append(NEWLINE);
    canonicalRequestString.append(signedHeadersValue);
    canonicalRequestString.append(NEWLINE);
    canonicalRequestString.append(payloadHash);

    AWS_LOGSTREAM_DEBUG(v4LogTag, "Canonical Request String: " << canonicalRequestString);

    //now compute sha256 on that request string
    auto hashResult = m_hash->Calculate(canonicalRequestString);
    if (!hashResult.IsSuccess())
    {
        AWS_LOGSTREAM_ERROR(v4LogTag, "Failed to hash (sha256) request string \"" << canonicalRequestString << "\"");
        return false;
    }

    auto sha256Digest = hashResult.GetResult();
    Aws::String cannonicalRequestHash = HashingUtils::HexEncode(sha256Digest);
    Aws::String simpleDate = now.ToGmtString(SIMPLE_DATE_FORMAT_STR);

    Aws::String stringToSign = GenerateStringToSign(dateHeaderValue, simpleDate, cannonicalRequestHash);
    auto finalSignature = GenerateSignature(credentials, stringToSign, simpleDate);

    Aws::StringStream ss;
    ss << AWS_HMAC_SHA256 << " " << CREDENTIAL << EQ << credentials.GetAWSAccessKeyId() << "/" << simpleDate
        << "/" << m_region << "/" << m_serviceName << "/" << AWS4_REQUEST << ", " << SIGNED_HEADERS << EQ
        << signedHeadersValue << ", " << SIGNATURE << EQ << finalSignature;

    auto awsAuthString = ss.str();
    AWS_LOGSTREAM_DEBUG(v4LogTag, "Signing request with: " << awsAuthString);
    request.SetAwsAuthorization(awsAuthString);

    return true;
}