To convert XML to JSON in Node-RED, here are the detailed steps, making it a fast and easy process:
- Install the XML Node: First, ensure you have the
node-red-node-xml
package installed. Go to your Node-RED editor, click the menu (hamburger icon) on the top right, select “Manage palette,” navigate to the “Install” tab, search fornode-red-node-xml
, and click “install.” This provides the essentialxml
node for parsing. - Drag and Drop Nodes:
- Inject Node: Drag an
inject
node onto your flow. This will be your trigger and where you’ll input your XML data. - XML Node: Drag an
xml
node (from the “parser” category) onto your flow. This is the core converter. - Debug Node: Drag a
debug
node onto your flow. This will display your JSON output in the debug sidebar.
- Inject Node: Drag an
- Connect the Nodes: Wire them in sequence:
inject
->xml
->debug
. - Configure the Inject Node:
- Double-click the
inject
node. - Change the “Payload” type to “string” (or “JSON” if your XML is already wrapped in a JSON string).
- Paste your XML content into the payload field. For example:
<root><item id="1">Data1</item><item id="2">Data2</item></root>
. - Set it to “Inject once after 0.1 seconds” for easy testing.
- Double-click the
- Configure the XML Node:
- Double-click the
xml
node. - Ensure “Action” is set to “Always convert to a JavaScript object.”
- The “Property” field should typically be
msg.payload
, as that’s where the XML data usually arrives from theinject
node. - You can set
attrkey
(for attributes) andcharkey
(for text content) if you want specific keys in your JSON output. - Set “Output as formatted JSON” to
true
if you want pretty-printed JSON.
- Double-click the
- Deploy and Test:
- Click the “Deploy” button in the top right corner.
- Click the square button on the
inject
node. - Check the debug sidebar (usually on the right of the Node-RED editor) to see your XML successfully converted into JSON. You’ll see a structured JavaScript object ready for further processing.
This setup creates a robust node red convert xml to json
workflow, handling various XML structures with ease.
Understanding XML to JSON Conversion in Node-RED
Converting data formats is a cornerstone of modern integration, and the transition from XML to JSON is incredibly common, especially when dealing with legacy systems or enterprise data exchanges that rely on XML, and newer APIs or web applications that prefer JSON. Node-RED, with its visual programming approach, simplifies this often complex task significantly. The core of this conversion within Node-RED relies on the node-red-node-xml
package, which provides a dedicated node to parse XML strings into JavaScript objects (which Node-RED inherently handles as JSON when passed between nodes). This process transforms the hierarchical, tag-based structure of XML into the key-value pair, array, and object structure of JSON, making it easier to manipulate and pass to other services or databases. For instance, consider a scenario where you receive shipment data in an XML format from an older logistics system. To integrate this with a modern inventory management API, you’d need to convert this XML into a JSON payload. Node-RED’s XML node automates this, streamlining the data flow and reducing manual parsing efforts. Statistics show that JSON’s adoption has surged, with over 70% of public APIs now preferring JSON over XML due to its lighter weight and ease of parsing in web environments.
Why XML to JSON? The Practical Benefits
The shift from XML to JSON is not just a trend; it’s driven by several practical advantages that make JSON more suitable for a vast array of applications, particularly in web services and mobile development. While XML remains prevalent in certain enterprise and industrial contexts (like SOAP services or financial data exchange standards such as FpML), JSON’s simplicity and native compatibility with JavaScript make it a go-to format for many.
- Lightweight Data Exchange: JSON is generally less verbose than XML. For example, to represent a simple user with a name and email, XML might require:
<user><name>John Doe</name><email>[email protected]</email></user>
, whereas JSON would be:{"user": {"name": "John Doe", "email": "[email protected]"}}
. This smaller footprint results in faster transmission times and reduced bandwidth consumption, which is critical for mobile applications and high-traffic APIs. A study by IBM in 2018 indicated that JSON payloads could be 10-30% smaller than equivalent XML payloads. - Easier Parsing and Manipulation: JSON’s structure directly maps to JavaScript objects, which means it can be parsed natively by JavaScript engines without the need for complex DOM parsers. This simplifies development, reduces code complexity, and improves execution speed in web browsers and Node.js environments. For developers, this translates to less boilerplate code and more focus on business logic.
- Readability: For many developers, JSON’s clean, bracket-and-brace syntax is more intuitive and easier to read than XML’s tag-based structure, especially when data is nested deeply. This enhances development efficiency and reduces the likelihood of parsing errors.
- Ubiquity in Web APIs: The vast majority of modern RESTful APIs communicate using JSON. Converting XML to JSON allows Node-RED flows to seamlessly interact with these contemporary services, whether it’s pushing data to a cloud platform, retrieving information from a third-party service, or integrating with microservices. This is crucial for building robust and interconnected systems. In fact, a survey from ProgrammableWeb showed that over 85% of new APIs published in the last five years used JSON as their primary data format.
The node-red-node-xml
Palette Explained
The node-red-node-xml
package is the linchpin for handling XML data within Node-RED. It provides a single, versatile node—the xml
node—that can perform both XML parsing (converting XML to a JavaScript object/JSON) and XML serialization (converting a JavaScript object/JSON back into an XML string). This dual functionality makes it an indispensable tool for bidirectional data transformation in integration flows.
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When you install this palette, the xml
node appears under the “parser” category in your Node-RED palette. Its primary function is to take an XML string, typically residing in msg.payload
, and parse it into a structured JavaScript object. This object can then be easily accessed and manipulated using change
nodes, function
nodes, or passed directly to other nodes that expect JSON input. The node also handles attributes, text content, and provides options for how these are represented in the resulting JSON. This is particularly useful when dealing with diverse XML schemas, from simple configurations to complex industry standards like HL7 for healthcare or FpML for finance. The xml
node supports various parsing options that allow fine-tuning the conversion process, ensuring that the output JSON accurately reflects the XML structure in a usable format.
Step-by-Step Installation of the XML Node
Before you can wield the power of XML-to-JSON conversion in Node-RED, you need to ensure the node-red-node-xml
palette is installed. This is a straightforward process within the Node-RED editor itself, requiring no command-line interaction if you have internet access. Json prettify extension firefox
- Open Node-RED Editor: Launch your Node-RED instance. This typically involves navigating to
http://localhost:1880
in your web browser, or the specific IP address and port where your Node-RED server is running. - Access the Menu: In the top right corner of the Node-RED editor, you’ll find a “hamburger” icon (three horizontal lines). Click this to open the main menu.
- Go to “Manage palette”: From the dropdown menu, select “Manage palette.” This will open a sidebar on the right side of your editor, dedicated to managing your installed nodes and discovering new ones.
- Navigate to the “Install” Tab: Within the “Manage palette” sidebar, you’ll see two tabs: “Nodes” (which lists your currently installed nodes) and “Install.” Click on the “Install” tab.
- Search for
node-red-node-xml
: In the search bar provided under the “Install” tab, typenode-red-node-xml
. The system will search the npm registry for available Node-RED nodes. - Install the Palette: Once
node-red-node-xml
appears in the search results, you will see an “install” button next to it. Click this button. A confirmation dialog will appear, asking if you want to install the package and its dependencies. Confirm the installation. - Verify Installation: After the installation completes (it usually takes a few seconds to a minute, depending on your internet connection), the
xml
node should now appear in your Node-RED palette on the left-hand side, typically under the “parser” category. You can also verify by going back to the “Nodes” tab in “Manage palette” and ensuringnode-red-node-xml
is listed as installed.
This process is generally seamless, reflecting Node-RED’s commitment to ease of use. A stable internet connection is key, as the installation fetches the necessary files from the npm registry.
Configuring the XML Node for Optimal Conversion
The xml
node in Node-RED is more than just a simple parser; it offers several configuration options that allow you to fine-tune how your XML data is converted into a JavaScript object, addressing various complexities that might arise from different XML structures. Understanding these options is key to achieving optimal and predictable JSON output.
- Action: This dropdown typically has two options: “Always convert to a JavaScript object” (XML to JSON/Object) and “Always convert to an XML string” (JSON/Object to XML). For our
xml to json node red
conversion, you’ll select “Always convert to a JavaScript object.” - Property: This field specifies which message property contains the XML string that needs to be parsed. By default, it’s set to
msg.payload
, which is the most common use case. If your XML data is stored in a different message property (e.g.,msg.xmlData
), you would change this field accordingly. attrkey
(Attribute Key): XML elements can have attributes (e.g.,<item id="1">
). When converted to JSON, these attributes need a place to live. Theattrkey
option defines the key name under which all attributes for an element will be grouped. The default value is_attr
. So,<item id="1" type="book">Book Name</item>
might become{"item": {"_attr": {"id": "1", "type": "book"}, "_text": "Book Name"}}
if_attr
is used.charkey
(Character Data Key): This option specifies the key name for the text content within an XML element. The default is_text
. So, if an XML element is<name>John Doe</name>
, its text content “John Doe” will be stored under the_text
key in the resulting JSON, like{"name": {"_text": "John Doe"}}
. If an element only has text and no attributes or child elements, its value might be directly assigned without_text
(depending oncompact
setting).pretty
(Pretty Output): This checkbox, when selected, ensures that the resulting JSON string (if you serialize it later or view it in the debug tab with JSON formatter) is nicely formatted with indentation, making it much more readable. While it doesn’t affect the internal JavaScript object structure, it’s immensely helpful for debugging and understanding the output.normalize
: Iftrue
, this option collapses adjacent text nodes into a single text node. This can clean up parsing output, especially if your XML has mixed content (text and elements interleaved). It’s generally recommended to keep itfalse
unless you have a specific need to normalize text.decode_entity
: Whentrue
(default), XML entities like&
(for&
) or<
(for<
) are automatically decoded into their corresponding characters. This ensures that the text content in your JSON is human-readable and doesn’t contain encoded characters.compact
: This is a crucial setting. Iftrue
, the XML node will attempt to create a more “compact” JSON representation. For instance, if an element has only text content and no attributes or child elements, its value might be directly assigned. E.g.,<name>John</name>
becomes{"name": "John"}
instead of{"name": {"_text": "John"}}
. This can make the JSON simpler, but might be less consistent if some elements have mixed content or attributes. It’s often set tofalse
for more predictable object structures that explicitly separate attributes and text.strict
: Whentrue
, the parser adheres strictly to XML specifications. If your XML is not perfectly well-formed, enabling strict mode might cause parsing errors. If you’re dealing with slightly malformed XML from external sources, you might need to set this tofalse
(though fixing the source XML is always the best practice).container
: This option allows you to specify a container property within themsg
object where the parsed JSON will be placed. The default ispayload
, meaning the converted JSON will overwritemsg.payload
. If you want to keep the originalmsg.payload
(e.g., if it was a large XML string you need for other purposes) and store the JSON elsewhere (e.g.,msg.parsedXml
), you can set this field.
For a typical xml to json node red
conversion where you want a clean, usable JavaScript object, the default settings for attrkey
and charkey
(_attr
, _text
) are often good starting points. You might toggle pretty
for debugging and compact
based on your desired output structure.
Practical XML to JSON Scenarios and Examples
Let’s dive into some real-world scenarios to illustrate how to handle different XML structures and convert them effectively using the xml
node in Node-RED. Understanding these patterns is essential for building robust integration flows.
Scenario 1: Simple XML with Attributes and Text
Imagine receiving basic product information from an older inventory system. Prettify json extension vscode
XML Input:
<product sku="P1001" category="Electronics">
<name>Laptop Pro</name>
<price currency="USD">1200.00</price>
<description>High performance laptop with 16GB RAM.</description>
</product>
Node-RED Flow:
- Inject Node: Configure its payload as a string and paste the XML above.
- XML Node:
- Action: “Always convert to a JavaScript object”
- Property:
msg.payload
attrkey
:_attr
(default)charkey
:_text
(default)compact
:false
(for clear distinction of text/attributes)pretty
:true
- Debug Node: Set to display
msg.payload
.
JSON Output:
{
"product": {
"_attr": {
"sku": "P1001",
"category": "Electronics"
},
"name": {
"_text": "Laptop Pro"
},
"price": {
"_attr": {
"currency": "USD"
},
"_text": "1200.00"
},
"description": {
"_text": "High performance laptop with 16GB RAM."
}
}
}
Key Takeaway: Notice how _attr
holds attributes and _text
holds the element’s text content. This explicit structure, achieved by compact: false
, makes the JSON predictable.
Scenario 2: XML with Multiple Child Elements of the Same Name
This is common for lists or collections. Things to do online free
XML Input:
<order id="ORD-001">
<customer name="Alice Smith"/>
<items>
<item id="A123">Pen</item>
<item id="B456">Notebook</item>
<item id="C789">Eraser</item>
</items>
</order>
Node-RED Flow (same as above, focus on XML node config):
compact
:false
(recommended for consistency)
JSON Output:
{
"order": {
"_attr": {
"id": "ORD-001"
},
"customer": {
"_attr": {
"name": "Alice Smith"
}
},
"items": {
"item": [
{
"_attr": {
"id": "A123"
},
"_text": "Pen"
},
{
"_attr": {
"id": "B456"
},
"_text": "Notebook"
},
{
"_attr": {
"id": "C789"
},
"_text": "Eraser"
}
]
}
}
}
Key Takeaway: When multiple child elements have the same name (<item>
here), the xml
node automatically converts them into a JSON array, making iteration easy in subsequent function
nodes.
Scenario 3: Using compact: true
for Simpler JSON
Sometimes, if elements only contain text and no attributes, you might want a flatter structure. Reverse binary calculator
XML Input:
<book>
<title>The Great Journey</title>
<author>Jane Doe</author>
<year>2023</year>
</book>
Node-RED Flow:
- XML Node:
compact
:true
(this is the key difference)
JSON Output:
{
"book": {
"title": "The Great Journey",
"author": "Jane Doe",
"year": "2023"
}
}
Key Takeaway: With compact: true
, _text
is omitted for elements that only contain simple text content, resulting in a more concise JSON structure. Be cautious: if an element sometimes has attributes or complex children, but sometimes just text, compact: true
can lead to inconsistent JSON structures, making downstream processing harder. Generally, compact: false
provides more predictable output, even if slightly more verbose.
These examples highlight the flexibility of the xml
node in node red convert xml to json
operations. Always test with your specific XML inputs to ensure the output matches your expectations for subsequent processing. Excel convert seconds to hms
Handling Large XML Files and Performance Considerations
While Node-RED is excellent for rapid prototyping and many integration tasks, processing very large XML files (e.g., hundreds of megabytes or even gigabytes) within a single flow can present performance challenges. Node-RED runs on Node.js, which is single-threaded by default, meaning that a computationally intensive operation like parsing a massive XML file can block the event loop, causing other flows or even the Node-RED editor to become unresponsive.
- Memory Usage: Converting a large XML string into a JavaScript object (JSON) requires a significant amount of memory. The in-memory representation of the XML tree can be several times larger than the raw XML string itself, especially if there are many attributes or deeply nested structures. For instance, parsing a 50MB XML file might consume 200MB or more of RAM. Running Node-RED on a system with limited RAM (e.g., a Raspberry Pi with 1GB) could lead to out-of-memory errors or severe performance degradation.
- CPU Cycles: Parsing involves traversing the XML tree, creating objects, and assigning properties. This is a CPU-intensive operation. For a large file, this can take a considerable amount of time, during which the Node.js event loop is tied up.
Strategies for Handling Large XML Files:
- Stream Processing (Advanced): For truly massive XML files, the ideal approach is stream processing, where you parse the XML incrementally without loading the entire document into memory. This involves using a SAX (Simple API for XML) parser or similar event-driven parsers. However, the standard
node-red-node-xml
does not natively support streaming for its XML-to-JSON conversion. If streaming is a hard requirement, you might need to:- Write a Custom Function Node (with external library): Use a
function
node and install a Node.js streaming XML parser library (e.g.,sax-js
,xml-flow
) directly into your Node-RED environment (requires command-linenpm install
in your Node-RED user directory). This is more complex and less “no-code.” - External Service/Microservice: Offload the parsing of very large files to a dedicated microservice or a separate script written in a language more suited for large-file processing (like Python with
lxml
or Java), and then have Node-RED call this service via HTTP or MQTT.
- Write a Custom Function Node (with external library): Use a
- Increase Node.js Memory Limit: For moderately large files (tens of megabytes), you might be able to increase Node.js’s default memory limit. You can do this by setting the
NODE_OPTIONS
environment variable before starting Node-RED:NODE_OPTIONS="--max-old-space-size=4096" node-red
(sets limit to 4GB). This is a temporary solution and not scalable for truly gigantic files. - Break Down XML: If possible, try to receive or process XML in smaller chunks. For example, if an API provides a large XML response, check if it supports pagination.
- Hardware Considerations: Ensure your Node-RED server has sufficient CPU power and RAM if you anticipate frequently processing large XML payloads. A cloud instance with more resources will naturally perform better than a low-spec embedded device. A typical commercial server handling enterprise integration might have 16GB+ RAM and multi-core CPUs.
- Benchmarking: Always benchmark your flows with representative data sizes to understand performance bottlenecks. Use the Node-RED debug tab to see message processing times.
For most typical integration scenarios involving XML messages up to several megabytes, the xml
node in Node-RED performs admirably without needing complex streaming solutions. However, being aware of these limitations and strategies is crucial for designing scalable and resilient xml to json node red
solutions.
Debugging XML to JSON Conversion Issues
Even with the best tools, things can sometimes go sideways. When your XML to JSON conversion in Node-RED isn’t producing the expected output, a systematic debugging approach can save you a lot of time and frustration. The Node-RED debug sidebar is your best friend here, but understanding common pitfalls is equally important.
-
No Output in Debug Sidebar: Free online survey tool canada
- Are nodes connected? Double-check all wires between your
inject
,xml
, anddebug
nodes. A broken wire means no data flow. - Is Debug Node Enabled? Ensure the
debug
node has its “active” checkbox ticked. Its light green indicator should be active. - Is Payload Correctly Injected? Verify that your
inject
node is actually sending the XML string. Temporarily wire theinject
node directly to adebug
node to see its raw output. Is the XML malformed or missing? - Error in
xml
Node? Check the Node-RED console (where Node-RED is running, e.g., your terminal window) for any error messages originating from thexml
node. Malformed XML can cause thexml
node to error out and stop the flow.
- Are nodes connected? Double-check all wires between your
-
Output is
null
orundefined
:- Empty Input? Ensure the
msg.payload
(or whatever property you specified in thexml
node’s “Property” field) actually contains an XML string. If it’s empty, the XML node will producenull
orundefined
. - Malformed XML: This is a frequent culprit. XML needs to be well-formed:
- Single Root Element: All XML must have exactly one root element (e.g.,
<root>...</root>
). - Correct Tag Nesting: Opening tags must match closing tags and be correctly nested (
<a><b></b></a>
, not<a><b></a></b>
). - Valid Characters: Ensure there are no invalid characters or unescaped special characters (
<
,>
,&
,'
,"
). Use<
,>
,&
,'
,"
for these.
- Single Root Element: All XML must have exactly one root element (e.g.,
strict
Mode: If your XML is slightly malformed or non-standard, setting thestrict
option tofalse
in thexml
node configuration might allow it to parse, though it’s always better to fix the source XML if possible.
- Empty Input? Ensure the
-
JSON Output Structure is Unexpected:
- Attributes and Text Mixed: If you expect simple key-value pairs but get
{ "element": { "_attr": {...}, "_text": "..." } }
, it’s likely due to theattrkey
andcharkey
settings, orcompact
beingfalse
. Review thexml
node configuration settings, especiallycompact
. - Arrays vs. Single Objects: If you have multiple elements with the same tag name (e.g.,
<item>A</item><item>B</item>
), thexml
node should convert them into an array. If it’s not, ensurecompact
is not leading to unexpected behavior. For consistency,compact: false
often provides a more predictable array structure. - Incorrect
attrkey
/charkey
: If your JSON keys for attributes or text content are not what you expect, check these specific settings in thexml
node. - Namespace Issues: If your XML uses namespaces (e.g.,
<ns:element>
), thexml
node processes them, but the resulting JSON might include namespace prefixes. If you need to clean these up, you’ll need afunction
node after thexml
node to iterate and modify the JSON structure.
- Attributes and Text Mixed: If you expect simple key-value pairs but get
-
Performance Issues (Slow Conversion):
- File Size: As discussed, very large XML files can cause slowdowns. Check the size of your input XML.
- System Resources: Monitor Node-RED’s CPU and memory usage using system tools (
top
, Task Manager). If they’re maxed out, consider increasing resources or implementing streaming solutions for extremely large files.
Debugging Workflow:
- Isolate the XML: Copy the exact XML string you’re sending to the
xml
node. Use an online XML validator (there are many free ones) to check if your XML is well-formed and valid. This often catches simple syntax errors. - Simplify the Flow: Temporarily remove any complex logic surrounding the
xml
node. Just useinject
->xml
->debug
. - Inspect
msg.payload
beforexml
node: Wire theinject
node directly to adebug
node to confirm the XML content is correctly being passed tomsg.payload
. - Step-by-step Debugging: Use the
debug
node effectively. Output the “Complete Message Object” if you need to see allmsg
properties, not just the payload. - Node-RED Logs: Keep an eye on the terminal or command prompt where Node-RED is running. Error messages often provide clues about what went wrong internally.
By systematically going through these steps, you can pinpoint issues related to xml to json node red
conversion and get your data flowing smoothly. Reverse binary number
Advanced Transformations Post-XML to JSON Conversion
Once your XML data has been successfully parsed into a JSON object by the xml
node, the real power of Node-RED comes into play. The resulting JSON is a standard JavaScript object, making it incredibly flexible for further manipulation, enrichment, and transformation to meet the exact requirements of your target system or application. This is where you typically use change
nodes and function
nodes to shape the data.
1. Data Renaming and Restructuring with change
Node
The change
node is a visual workhorse for simple data manipulation. You can use it to:
- Rename Properties: If your XML node output
_attr.id
but your target API expectsproduct_id
, you can setmsg.payload.product_id
tomsg.payload._attr.id
and then deletemsg.payload._attr
. - Move Properties: Shift properties from one nested level to another. For example, if
msg.payload.order.items.item
is an array of objects, and you want to lift theitem
array directly undermsg.payload.items
, you can achieve this by settingmsg.payload.items
tomsg.payload.order.items.item
. - Delete Properties: Remove unwanted keys like
_attr
or_text
if you’ve already extracted the values you need. - Set Fixed Values: Add new properties with static values (e.g.,
msg.payload.status = "processed"
). - Concatenate Strings: Combine multiple fields into a single string.
Example: Renaming and Deleting
Let’s say your xml
node output:
{"product": {"_attr": {"sku": "P1001"}, "_text": "Laptop"}}
And you want:
{"product_id": "P1001", "name": "Laptop"}
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change
Node Configuration:
- Set:
msg.payload.product_id
tomsg.payload.product._attr.sku
- Set:
msg.payload.name
tomsg.payload.product._text
- Delete:
msg.payload.product
This is highly efficient for straightforward mapping tasks.
2. Complex Logic and Iteration with function
Node
For more intricate transformations, conditional logic, loops, or integrating external libraries, the function
node is indispensable. It allows you to write JavaScript code directly within your flow.
- Iterating Arrays: If your JSON contains an array (e.g., a list of
items
from a repeated XML element), you can loop through this array to process each item individually.// Example: Process each item in an array if (msg.payload.order && msg.payload.order.items && Array.isArray(msg.payload.order.items.item)) { msg.payload.order.items.item.forEach(item => { // Transform item properties, e.g., rename _attr.id to itemId if (item._attr && item._attr.id) { item.itemId = item._attr.id; delete item._attr; } if (item._text) { item.description = item._text; delete item._text; } }); } return msg;
- Conditional Logic: Perform different transformations based on data values.
if (msg.payload.product.price < 100) { msg.payload.category = "Budget"; } else { msg.payload.category = "Premium"; } return msg;
- Date Formatting: Convert date strings from one format to another.
- Calculations: Perform mathematical operations on numeric fields.
- External Library Integration: If you need advanced data manipulation (e.g., complex hashing, specific data validation), you can import external Node.js modules into your
function
node (requires managing Node-RED’s package dependencies).
3. Enriching Data with External Lookups
After converting XML to JSON, you might need to enrich the data by fetching additional information from other sources (databases, APIs).
- Database Lookup: Use
node-red-node-mysql
,node-red-node-sqlite
, or other database nodes to query a database using data from your parsed JSON (e.g., look up product details using an SKU). - API Calls: Use an
http request
node to call another REST API, passing part of your JSON as a query parameter or request body, and then merge the API response back into your message.
By combining the xml
node with powerful transformation nodes, Node-RED becomes an incredibly versatile tool for handling complex data integration challenges, ensuring your xml to json node red
flows deliver precisely the data your applications need. Free online assessment tools for recruitment
FAQ
What is the purpose of converting XML to JSON in Node-RED?
The purpose of converting XML to JSON in Node-RED is primarily to facilitate data integration with modern web services and applications. JSON is lighter, easier to parse in JavaScript environments, and is the preferred format for most RESTful APIs, making it simpler to consume, manipulate, and transfer data once converted.
How do I install the XML node in Node-RED?
To install the XML node in Node-RED, open your Node-RED editor, click the menu icon (hamburger) in the top-right corner, select “Manage palette,” go to the “Install” tab, search for node-red-node-xml
, and click the “install” button.
Can Node-RED convert JSON back to XML?
Yes, the same xml
node from the node-red-node-xml
palette can convert JSON (JavaScript objects) back to XML. In its configuration, you simply set the “Action” property to “Always convert to an XML string.”
What happens to XML attributes when converted to JSON?
When XML attributes are converted to JSON using the xml
node, they are typically grouped under a special key within the element’s object representation. By default, this key is _attr
, but you can configure it using the attrkey
option in the xml
node settings.
How does the compact
option affect XML to JSON conversion?
The compact
option in the xml
node controls the verbosity of the generated JSON. If compact
is true
, simple elements with only text content (no attributes or child elements) will have their text directly assigned as the property value (e.g., {"name": "John"}
). If compact
is false
(default), the text content is placed under a dedicated _text
key (e.g., {"name": {"_text": "John"}}
), providing a more consistent structure, especially for elements that might sometimes have attributes. Online meeting schedule
What should I do if my XML is malformed and causes errors?
If your XML is malformed (e.g., missing closing tags, invalid characters, multiple root elements), the xml
node will likely throw an error. First, try to validate your XML using an online XML validator. If you cannot fix the source XML, you can try setting the strict
option to false
in the xml
node’s configuration, though this is not a guaranteed solution and fixing the source is always recommended.
How can I handle large XML files in Node-RED?
Handling very large XML files (hundreds of MBs to GBs) directly in Node-RED’s xml
node can cause memory issues or block the event loop. For such cases, consider:
- Increasing Node.js’s memory limit.
- Implementing stream-based parsing using a custom
function
node and an external Node.js streaming XML parser library (more complex). - Offloading the parsing to an external microservice or dedicated script.
Where does the converted JSON output appear?
The converted JSON output, by default, replaces the msg.payload
property. You can view this output in the Node-RED debug sidebar by connecting a debug
node (configured to display msg.payload
or “complete message object”) after your xml
node.
Can I rename JSON keys after conversion?
Yes, you can easily rename JSON keys after conversion. The most common way to do this is using a change
node, where you can set new properties based on existing ones and then delete the old ones. For more complex renaming or conditional logic, a function
node is also suitable.
What is the attrkey
and charkey
for in the XML node?
attrkey
defines the property name under which XML attributes are stored in the resulting JSON object (default: _attr
). charkey
defines the property name for the text content of an XML element (default: _text
), especially when compact
is false
. Random bytes golang
Is Node-RED’s XML to JSON conversion suitable for production environments?
Yes, Node-RED’s XML to JSON conversion, particularly with the node-red-node-xml
palette, is widely used in production environments for various integration tasks, especially for message sizes up to several megabytes. For extremely high-volume or very large file processing, resource allocation and flow design (e.g., offloading heavy parsing) need to be carefully considered.
How can I test my XML to JSON flow in Node-RED?
You can test your XML to JSON flow by using an inject
node configured with your XML string payload. Connect this to the xml
node and then to a debug
node. Clicking the inject
node’s button will trigger the flow and display the JSON output in the debug sidebar.
What are common alternatives to Node-RED for XML to JSON conversion?
Common alternatives for XML to JSON conversion include:
- Programming Languages: Python (with
xml.etree.ElementTree
orlxml
), Java (with JAXB, DOM, SAX), Node.js (withxml2js
,fast-xml-parser
). - Dedicated Integration Platforms: Apache Camel, MuleSoft, Microsoft BizTalk Server.
- Online Converters: Various web-based tools that allow you to paste XML and get JSON output.
Can I transform XML namespaces during conversion?
The xml
node will parse XML with namespaces, and the resulting JSON will include the namespace prefixes. If you need to remove or remap these prefixes, you would typically use a function
node after the xml
node to programmatically clean up the JSON object.
How do I handle multiple root elements in an XML string?
XML strictly requires a single root element. If your input string contains multiple root elements (e.g., <item>1</item><item>2</item>
), it is not well-formed XML and the xml
node will fail to parse it. You must wrap such fragments in a single parent element (e.g., <root><item>1</item><item>2</item></root>
) before feeding it to the xml
node. Random bytes python
What is the default output format for numbers and booleans from XML?
By default, the xml
node treats all text content and attribute values as strings. If your XML contains numeric or boolean values, they will remain strings in the JSON output (e.g., "123"
, "true"
). You will need to use a change
node (using JSONata expressions) or a function
node to explicitly convert these strings to their correct data types (number, boolean) if required by your downstream applications.
Can I specify which properties to convert or ignore?
The xml
node converts the entire XML structure into a JSON object based on its parsing rules. It doesn’t offer direct configuration to selectively convert or ignore specific XML elements or attributes during the initial parsing. However, once the full JSON object is created, you can use change
nodes or function
nodes to filter, extract, or delete unwanted properties.
How does the decode_entity
option work?
The decode_entity
option, when enabled (default true
), tells the xml
node to decode XML entities like &
(for &
), <
(for <
), and >
(for >
) into their actual character representations in the resulting JSON string. This ensures that the text content is human-readable and correctly interpreted.
What are the main benefits of using Node-RED for XML to JSON conversion over coding?
The main benefits of using Node-RED for XML to JSON conversion over traditional coding include:
- Visual Programming: Node-RED’s drag-and-drop interface significantly speeds up development and makes complex flows easier to understand and debug.
- Rapid Prototyping: You can quickly build and test integration flows without writing extensive code.
- Ease of Deployment: Flows are easily deployed and managed within the Node-RED environment.
- Reduced Boilerplate Code: Pre-built nodes handle common tasks like parsing, HTTP requests, and debugging, reducing the need for custom code.
- Accessibility: Non-programmers can often understand and even contribute to flow development.
Can I transform the JSON output from the XML node using JSONata?
Yes, absolutely! JSONata is a powerful query and transformation language integrated directly into Node-RED’s change
nodes (and callable within function
nodes). After the xml
node generates the initial JSON, you can use a change
node with a JSONata expression to deeply query, filter, map, and reshape the JSON output into any desired structure, making it incredibly flexible for advanced transformations. Word wrap css
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