Update JSON file using PowerShell
<p>I am currently trying to setup a continuous integration system using VSTS and have run into a bit of a snag. As part of the release process I need to update a specific object value in a JSON file depending on the environment. The only tools it seems I have at my disposal that might get this done in the VSTS environment is PowerShell.</p>

<p>I've done quite a bit of research and have not been able to figure out how exactly this can be done. I found this question and answer here on Stack Overflow "<a href="https://stackoverflow.com/questions/35865272/how-do-i-update-json-file-using-powershell">How do I update JSON file using PowerShell</a>" but executing the script provided in the answer changes the structure of the JSON file substantially and adds quite a bit of what looks like PowerShell metadata.</p>

<p>Ideally, I would like to take an existing JSON file that gets deployed and update the value of the connectionString property in the example JSON below.</p>

<pre><code>{
    "policies": {
         "Framework.DataContext": {
         "connectionString": "Server=ServerName;Database=DateBaseName;Integrated Security=sspi;"
         }
    }
}
</code></pre>

<p>Does anyone have any advice on how to accomplish this? So far I have tried running the following script but it throws an "The property 'connectionString' cannot be found on this object. Verify that the property exists and can be set." exception. I have verified that the object traversal is correct and the connectionString property exists. </p>

<pre><code>$pathToJson = "D:\Path\To\JSON\file.json"
$a = Get-Content $pathToJson | ConvertFrom-Json
$a.policies.'Framework.DataContext'.connectionString = "Server=ServerName;Database=DateBaseName;Integrated Security=sspi;"
$a | ConvertTo-Json | set-content $pathToJson
</code></pre>

<p>The full contents of file.json are as follows</p>

<pre><code>{
"log": {
    "level": 0,
    "file": "c:\\temp\\simport.log",
    "formats": {
        "error": null,
        "start": null,
        "requestBegin": null,
        "requestWork": "",
        "requestError": null,
        "requestEnd": null,
        "stop": null
    },
    "eventLog": {
        "name": "Application"
    }
},

"diagnostic": {
    "stackTrace": false
},

"api": {
    "simport": true
},

"roles": {
    "0": "Anonymous",
    "1": "Administrator",
    "2": "Participant",
    "3": "Facilitator"
},

"pathType": {
    "area": 1,
    "region": 2,
    "session": 3,
    "team": 4
},

"scenarios": {
    "default": {
       "default": true,
        "initState": "Init",
        "rounds": [
            {
                "name": "round1",
                "displayName": "R1",
                "beginTime": 1,
                "endTime": 3
            },
            {
                "name": "round2",
                "displayName": "R2",
                "beginTime": 4,
                "endTime": 6
            },
            {
                "name": "round3",
                "displayName": "R3",
                "beginTime": 7,
                "endTime": 9
            },
            {
                "name": "round4",
                "displayName": "R4",
                "beginTime": 10,
                "endTime": 12
            }
        ]
    }
},

"simportQueries": {
    "package": "bin/trc.simport3.zip"
},

"customQueries": {
    "package": "app/config/custom-queries.zip",
    "parameters": {
    }
},

"audit": {
    "Path.Create": true,
    "Path.Delete": true,
    "Team.Create": true,
    "Team.Update": true,
    "Team.Delete": true,
    "SimportData.SaveValues": true
},

"tasks": {
    "task1": {
        "state": "",
        "required": "",
        "completed": "C:Task1Status:+0"
    }
},

"feedback": {
    "welcome": {
        "text": {
            "": "en-us",
            "en-us": "Welcome"
        }
    }
},

"contentCategories": {
    "demo1": {
        "round": 1
    }
},

"policies": {
    "Simport.Web.Module": {
        "fileMask": ".aspx,.asmx",
        "deny": {
            "statusCode": 404,
            "statusDescription": "Not found",
            "location": [
                "/{0,1}app/config/(.*\\.json)$",
                "/{0,1}app/config/(.*\\.xml)$",
                "/{0,1}app/config/(.*\\.zip)$",
                "/{0,1}app/config/(.*\\.xlsx)$"
            ]
        },
        "formDataContentType": [ "application/x-www-form-urlencoded" ]
    },

    "Framework.DataContext": {
        "connectionString": "Server=(local);Database=Simport3;Integrated Security=sspi;",
        "commandTimeout": 30
    },

    "Simport.Security": {
        "passwordEncryption": "",
        "passwordSalt": "",
        "passwordPolicy": {
            "disabled": true,
            "min": 8,
            "max": 100,
            "rules": [
                { "id": "digit", "pattern": "\\d+", "flags": "i" },
                { "id": "letter", "pattern": "\\w+", "flags": "i" },
                { "id": "upper", "pattern": "[A-Z]+" },
                { "id": "lower", "pattern": "[a-z]+" },
                { "id": "special", "pattern": "[\\!#@\\$_~]+", "flags": "i" },
                { "id": "prohibited", "pattern": "[\\\\/'\"\\?\\^&amp;\\+\\-\\*\\%\\:;,\\.]+", "flags": "gi", "match": false }
            ]
        }
    },

    "Simport.PackageDefinition": {
        "path": "~/app/config/manifest.xml"
    },

    "Security.SignIn": {
        "result": {
            "default": "u,p,p.props,t"
        },
        "claims": [
            [ "userId", "firstName", "lastName" ]
        ]
    },

    "Security.GetContext": {
        "result": {
            "default": "u,p,p.props,pr,t"
        }
    },

    "Security.ChangePassword": {
        "allowedRoles": [ 1, 2, 3 ]
    },

    "Security.ResetPassword": {
        "allowedRoles": [ 1, 2 ]
    },

    "Security.Register": {
        "allowedRoles": [ 0 ],
        "!pathType-0": 4,
        "!roleId-0": 2
    },

    "Path.Create": {
        "allowedRoles": [ 1, 2, 3 ]
    },

    "Path.Select": {
        "allowedRoles": [ 1, 2, 3 ],
        "result-1": {
        }
    },

    "Path.Delete": {
        "allowedRoles": [ 1, 2 ]
    },

    "User.Select": {
        "allowedRoles": [ 1, 2, 3 ],
        "result": {
            "select": [ "id", "pathid", "roleid", "name", "email", "login", "props" ],
            "restrict": [ "password" ]
        },
        "result-1": {
            "select": "*",
            "group": true
        }
    },

    "User.Create": {
        "allowedRoles": [ 1, 2 ],
        "result": {
            "select": [ "id", "pathid", "roleid", "name", "email", "login", "props" ],
            "restrict": [ "password" ]
        },
        "result-1": {
            "select": "*",
            "group": true
        }
    },

    "User.Update": {
        "allowedRoles": [ 1, 2, 3 ],
        "result": {
            "select": [ "id", "pathid", "roleid", "name", "email", "login", "props" ],
            "restrict": [ "password" ]
        }
    },

    "User.Delete": {
        "allowedRoles": [ 1, 2 ],
        "result": {
            "restrict": [ "password" ]
        }
    },

    "Session.Select": {
        "allowedRoles": [ 1, 2, 3 ],
        "enforcePathLevel": true,
        "result": {
            "default": [ "name", "beginDate", "endDate" ],
            "restrict": [ "password" ]
        },
        "result-1": {
            "default": [ "name", "beginDate", "endDate" ],
            "treeAllowed": true,
            "treeDefault": false
        }
    },

    "Session.Create": {
        "allowedRoles": [ 1, 2 ],
        "enforcePathLevel": true
    },

    "Session.Update": {
        "allowedRoles": [ 1, 2 ],
        "enforcePathLevel": true,
        "update-restictions": [ "password" ],
        "update-restictions-1": [ ],
        "result": {
            "restrict": [ "password" ]
        }
    },

    "Session.Delete": {
        "allowedRoles": [ 1, 2 ],
        "result": {
            "restrict": [ "password" ]
        }
    },

    "Team.Select": {
        "allowedRoles": [ 1, 2, 3 ],
        "enforcePathLevel": false,
        "enforcePathLevel-1": true,
        "result-1": {
            "treeAllowed": true,
            "treeDefault": false
        }
    },

    "Team.Create": {
        "allowedRoles": [ 1, 2, 3 ],
        "enforcePathLevel": true,
        "enforcePathLevel-1": false,
        "allowMultiple": false,
        "allowMultiple-1": true,
        "result": {
        },
        "overrides": {
            "roleID": 3
        }
    },

    "Team.Reset": {
        "allowedRoles": [ 1, 2, 3 ]
    },

    "Team.Delete": {
        "allowedRoles": [ 1, 2, 3 ],
        "deleteMultiple": true,
        "result": {
            "default": "t"
        }
    },

    "Team.TransitionTo": {
        "allowedRoles": [ 1, 2, 3 ],
        "inboundRules": {
            "Round1Init": {
                "allowedRoles": [ ]
            }
        },
        "outboundRules": {
            "Round1Wait": {
                "allowedRoles": [ 1, 2, 3 ]
            }
        }
    },

    "Team.TakeControl": {
        "allowedRoles": [ 1, 2, 3, 4 ],
        "select-1": {
            "select": "*",
            "restrict": [ "ctrl.userID", "ctrl.loginName" ]
        }
    },

    "Team.ReleaseControl": {
        "allowedRoles": [ 1, 2, 3, 4 ],
        "select-1": {
            "select": "*",
            "restrict": [ "ctrl.userID", "ctrl.loginName" ]
        }
    },

    "Team.GetStatus": {
        "allowedRoles": [ 1, 2, 3 ],
        "result": {
            "default": "p,t,pr"
        }
    },

    "Data.Select": {
        "allowedRoles": [ 1, 2, 3 ]
    },

    "Data.Update": {
        "allowedRoles": [ 1, 2, 3 ],
        "audit": {
            "g": false,
            "i": true,
            "o": true,
            "s": true
        }
    },

    "Data.ExecuteQuery": {
        "allowedRoles": [ 0, 1, 2, 3 ],
        "allowed-0": [ "login4\\areas", "login4\\regions", "login4\\sessions", "login4\\teams" ],
        "restrict-3": [ "prohibitedQueryNameHere" ]
    },

    "Document.Select": {
        "defaultTextEncoding": "utf-16"
    },

    "Document.Create": {
        "~allowFileExt": [ ],
        "denyFileExt": [ ".exe", ".com", ".cmd", ".bat", ".ps1" ],
        "~allowContentType": [ ],
        "denyContentType": [ "application/x-msdownload" ],
        "maxContentLength": 0,
        "defaultTextEncoding": "utf-16"
    },

    "Document.Update": {
        "allowedRoles": [ 1, 2, 3 ]
    },

    "Document.Delete": {
    },

    "Document.Download": {
    }
}
}
</code></pre>