title: json_decode() does not work with this valid JSON string
body: <p>Here is the JSON string my app is receiving from Postmark, an inbound email delivery service:</p>
  
  <pre><code>{
    "From": "me@mydomain.com",
    "FromFull": {
      "Email": "me@mydomain.com",
      "Name": "Jack"
    },
    "To": "\"test@email.mydomain.com\" &lt;test@email.mydomain.com&gt;",
    "ToFull": [
      {
        "Email": "test@email.mydomain.com",
        "Name": "test@email.mydomain.com"
      }
    ],
    "Cc": "",
    "CcFull": [],
    "ReplyTo": "",
    "Subject": "Brussel Sprouts",
    "MessageID": "a97fb074-338e-48c5-97db-d9c5155e9307",
    "Date": "Sun, 30 Dec 2012 18:10:54 +0000",
    "MailboxHash": "",
    "TextBody": "Are Nice",
    "HtmlBody": "",
    "Tag": "",
    "Headers": [
      {
        "Name": "X-Spam-Checker-Version",
        "Value": "SpamAssassin 3.3.1 (2010-03-16) onrs-iad-pm-inbound1.wildbit.com"
      },
      {
        "Name": "X-Spam-Status",
        "Value": "No"
      },
      {
        "Name": "X-Spam-Score",
        "Value": "0.0"
      },
      {
        "Name": "X-Spam-Tests",
        "Value": "RCVD_IN_DNSWL_BLOCKED"
      },
      {
        "Name": "Received-SPF",
        "Value": "None (no SPF record) identity=mailfrom; client-ip=209.85.212.175; helo=mail-wi0-f175.google.com; envelope-from=me@mydomain.com; receiver=test@email.mydomain.com.com"
      },
      {
        "Name": "X-Google-DKIM-Signature",
        "Value": "v=1; a=rsa-sha256; c=relaxed\/relaxed;        d=google.com; s=20120113;        h=x-received:from:content-type:content-transfer-encoding:subject         :message-id:date:to:mime-version:x-mailer:x-gm-message-state;        bh=JrLpPQqTnp0QixED2qZ5+zepXQXuPLJWqihFECt8uJ4=;        b=EJHac6BaGi3laxnMZZ3Lf\/ervtavKTG0+DHXRRCfGH2HSG42wN\/qIj6IQ0G36NFsjT         x2tnYRhj7aBRseky+YEyAF99kUOx\/p8qaCWo7wN1cf3dTJUrrQu\/vrdgdXezfheKW49z         x4\/d\/8f2bgJN5MvTtZj15WmqZRCDt8\/QJVZvP7J5hANdxqULgwAJCaCJFU3CTNu66nT+         M1tPSDfZwTdNsS70Pna75Y3bRtlJPxXF6gesYhXK\/cnDbqsCopcAiEc9guMVMnqAjIRu         XqBWLft4Bom5H2ViNj5V\/A3GCmP44h\/OM1h+h2zBTYJ3fJK4zyluok8K5GIjn9KN1o2w         v4eA=="
      },
      {
        "Name": "X-Received",
        "Value": "by 10.180.72.146 with SMTP id d18mr51711599wiv.33.1356891056971;        Sun, 30 Dec 2012 10:10:56 -0800 (PST)"
      },
      {
        "Name": "Content-Transfer-Encoding",
        "Value": "7bit"
      },
      {
        "Name": "Message-Id",
        "Value": "&lt;224B85F9-B9C2-4273-A81C-7C340E8A66B2@mydomain.com&gt;"
      },
      {
        "Name": "Mime-Version",
        "Value": "1.0 (Mac OS X Mail 6.2 \\(1499\\))"
      },
      {
        "Name": "X-Mailer",
        "Value": "Apple Mail (2.1499)"
      },
      {
        "Name": "X-Gm-Message-State",
        "Value": "ALoCoQl0eQmrBNRNbe7T06oTeDXcEA3LDLJurR2U0Yj64EyOA2Iy3YL6CyiTodGXtuJHIuMlm5a1"
      }
    ],
    "Attachments": []
  }
  </code></pre>
  
  <p>Copy that into any JSON Validator and you'll see that it is valid.</p>
  
  <p>However, when I run <code>json_decode();</code> on this string in PHP, it fails silently. When running <code>echo json_last_error();</code> the returned error code is <code>4</code>. This corresponds to a Syntax Error.</p>
  
  <p>By simply find-replacing <code>\</code> to <code>\\</code> in my code editor, I can get this to work, but how can I get PHP to automatically do this?</p>
  
  <p><strong>EDIT:</strong> As discovered in the comments, the exact string I posted above works correctly when read in from a file, as PHP does not try to parse any backslashes etc. However, it appears to be parsing the slashes when read in from <code>file_get_contents('php://input)</code> which is what is now causing me problems.</p>