public static String buildCanonicalString()

in src/main/java/com/aliyun/oss/internal/SignUtils.java [51:101]
39 lines of code
12 McCabe index (conditional complexity)

    public static String buildCanonicalString(String method, String resourcePath, RequestMessage request,
            String expires) {

        StringBuilder canonicalString = new StringBuilder();
        canonicalString.append(method).append(SignParameters.NEW_LINE);

        Map<String, String> headers = request.getHeaders();
        TreeMap<String, String> headersToSign = new TreeMap<String, String>();

        if (headers != null) {
            for (Entry<String, String> header : headers.entrySet()) {
                if (header.getKey() == null) {
                    continue;
                }

                String lowerKey = header.getKey().toLowerCase();
                if (lowerKey.equals(HttpHeaders.CONTENT_TYPE.toLowerCase())
                        || lowerKey.equals(HttpHeaders.CONTENT_MD5.toLowerCase())
                        || lowerKey.equals(HttpHeaders.DATE.toLowerCase())
                        || lowerKey.startsWith(OSSHeaders.OSS_PREFIX)) {
                    headersToSign.put(lowerKey, header.getValue().trim());
                }
            }
        }

        if (!headersToSign.containsKey(HttpHeaders.CONTENT_TYPE.toLowerCase())) {
            headersToSign.put(HttpHeaders.CONTENT_TYPE.toLowerCase(), "");
        }
        if (!headersToSign.containsKey(HttpHeaders.CONTENT_MD5.toLowerCase())) {
            headersToSign.put(HttpHeaders.CONTENT_MD5.toLowerCase(), "");
        }

        // Append all headers to sign to canonical string
        for (Map.Entry<String, String> entry : headersToSign.entrySet()) {
            String key = entry.getKey();
            Object value = entry.getValue();

            if (key.startsWith(OSSHeaders.OSS_PREFIX)) {
                canonicalString.append(key).append(':').append(value);
            } else {
                canonicalString.append(value);
            }

            canonicalString.append(SignParameters.NEW_LINE);
        }

        // Append canonical resource to canonical string
        canonicalString.append(buildCanonicalizedResource(resourcePath, request.getParameters()));

        return canonicalString.toString();
    }